Monday, May 3, 2010
Thursday, March 25, 2010
Cascading Style Sheets (CCS) is a language used to describe the look and format of a document written in a markup language from an external document. CSS is most commonly used today with HTML and XHTML to control the appearance of websites; however, it can also be applied to any type of XML document.
History of CSS
Various forms of external style sheets have existing since the 1970’s. CSS as we know it has been in development since the early 1990’s. When the concept of style sheets for XML languages was first proposed, nine different languages were considered. Two of these languages, Cascading HTML Style Sheets and Stream-based style sheets, became the foundation for CSS Level 1. In 1995, the World Wide Web Consortium became interested in CSS, and by the end of 1996 CSS Level 1 was officially recommended by the W3C. After the release of CSS1, the W3C went back to work improving CSS and developing CSS2, which was released in 1997. W3C has been working on CSS3 since 1998 and it is still in development.
Problems with CSS
While the theory behind Cascading Style Sheets is sound, its execution has had problems. The biggest problem CSS faced, and still faces today, is browser adoption. Internet Explorer 3 was released in 1996 and was the first browser that supported CSS however the extent of the support was minimal. It was not until 2000, with the release of Internet Explorer 5, that browsers almost completely supported CSS1. Other early browsers had minimal support but there were also serious incompatibilities. Only now are browsers starting to more fully support CSS2.
The most common of these support problems is with older versions of Internet Explorer—it is called the box model. Ordinarily, in compliance with W3C standards, the “width” that is specified is for the content. This “width” is then surrounded by padding, border and the margin in that order. Each of these levels adds to the overall width of the original content. In Internet Explorer the “width” refers to the width of the content, plus padding and the border. Margins are added on the outside of the “width” addition. The end result is that websites can look different between Internet Explorer and other browsers unintentionally. Various fixes have been made available and newer versions of Internet Explorer have since resolved this problem.
Why Use CSS?
CSS is used to separate the content of the document with the code to style each page. This allows for increased accessibility and increased flexibility, especially across different browsers, since different style sheets can be applied depending on the browser. CSS can be applied quickly and easily across multiple pages of content, allowing for easy maintenance and reformatting. CSS requires less bandwidth, since the style sheet only has to load once and then the browser will store the information making websites load faster where there is a lower bandwidth.
The most important reason to use CSS, however, is that it is remarkably powerful despite some of its shortcomings. The best demonstration of this is at www.csszengarden.com. This website allows users to take standard HTML and change the appearance just through CSS.
What is Twitter?Twitter can be categorized as anything from a microblogging application (similar to a blog except instead of long passages, the entries are merely just short sentences or fragments), to a social instant messaging client. The fundamental idea of twitter is that a person logs into their account, they add friends, who are called “followers”, and they then send short messages (“tweets”) to them. These messages can be no longer than 140 characters and can be received through text messages, through instant messaging, through Twitter’s website or through other third-party applications.
How has it been integrated into our society?Many people question the value of this service, and wonder how useful is it to know what your friends are up to every hour, and vice-versa. Although on a micro level, messages may seem insignificant, but over a period of time, people have gained insight into their friends’ lives that they would never otherwise, such as what their daily habits are, or how they feel throughout the day. Twitter has also become an outlet for real-time news. For example, when there was an earthquake in San Francisco, a message was sent out asking, “was that an earthquake?” Within minutes, somebody else responded confirming his question, and then guessing what the magnitude was. This quickly was responded with someone who had looked up what the magnitude actually was, and so on and so forth. More or less, news had spread using only sentences that were less than 140 characters. A San Antonio-based market research firm Pear Analytics that analyzed 2,000 tweets (originating from the US and in English) over a 2-week period from 11:00am to 5:00pm found that only 4% of the tweets was actually about news. The other 41% was pointless babble, 38% was conversational, 9% had pass-along value, 6% was self-promotion, and the remaining 4% was spam. But in general, in addition to mundane personal information, Twitter also serves as a tool in politics, campaigns, public relations, protests, and is proven to be incredibly useful in branding and marketing. In fact 17% of Britain’s small businesses are using Twitter. They claim that it is a very effective way to attract new customers, and have saved them significant amounts of money (upto $8,000 in some cases) in advertising and other promotions. In the United States, large companies such as Dell, said that using Twitter in addition to Facebook and blogs, they have generated $9 million in direct sales. Thus it’s no surprise that the largest age segment on Twitter actually is 35-49yr olds. Approximately 62% of the 3 million users of access Twitter though work.
So how did this enormous service begin in the first place?The idea originated in the mid of Jack Dorsey, a co-founder of the website. Dorsey, merely 14yrs old, worked as a software developer in his hometown, St. Louis. At the age of 18, he was admitted into NYU, where he began working at one of the largest courier services in the country, DMS, where he continued to write dispatch software. His fascination over the fact that the users of the software (general drivers, couriers, limo/taxi drivers) were just reporting what they were doing by stripping information down to it’s simplest form, served as inspiration for the idea behind Twitter. Putting the idea on hold for a couple of years, Dorsey went to California and launched his own company, during which he continued to work out his idea of combining dispatch software, instant messaging and text messaging to create real-time communication. Then in 2006, he proposed his idea to the podcasting company, ODEO. Through the company he formed a partnership with Biz Stone and Evan Williams, who eventually became co-founders of Twitter. In barely two weeks they came up with a prototype for Twitter, and then officially launched it in July 2006. By 2007, Twitter had established itself as its own company.
Future GrowthSince 2008, Twitter has grown from 475,000 users to 7,038,00 users in 2009 at an unbelievable growth rate of 1382%. At this point, Twitter is working on improving their very basic search engine that eliminates duplicates and other “noise” that comes up during searches. They are also working on embedding geographic locations into Tweets. Their latest addition to the site is a potentially powerful tool called the Twitter Lists, which allows users to create custom lists of Twitter accounts, which then can be shared or kept private.
Sources:http://help.twitter.com/forums/10711/entries/76460 http://www.thedailyanchor.com/2009/02/12/a-conversation-with-twitter-co-founder-jack-dorsey/ http://dev.aol.com/article/2007/04/definitive-guide-to-twitter http://www.pcpro.co.uk/news/enterprise/356044/twitter-earned-dell-9-million http://www.economist.com/specialreports/displaystory.cfm?story_id=15350940 http://www.quantcast.com/twitter.com#demographics a b Kelly, Ryan, ed. (2009-08-12), "Twitter Study - August 2009" (PDF), Twitter Study Reveals Interesting Results About Usage, San Antonio, Texas: Pear Analytics, http://www.pearanalytics.com/wp-content/uploads/2009/08/Twitter-Study-August-2009.pdf, retrieved 2009-08-18
Instant Messaging, also known as IM, is a method where two or more people can send fast real-time “text-based” communication on computers or a variety of other electronic devices over a network (usually the Internet). Currently in the marketplace, Instant Messaging is very widespread as it has become a popular form of communication at college, work and at home. Everyday millions of people use Instant Messaging as a form communication as our society is becoming more and more dependent on it. It also allows people to communicate internationally at real-time, which gives a new experience of interaction online rather than just purely sending e-mail. In todays fast past society, people are always looking for new ways to save time as people would often rather Instant Message than e-mail a co-worker or friend due to time and efficiency.
History of Instant Messaging
Although Instant Messaging is currently thought as utilizing such clients as AOL Instant Messenger, Google Chat, MSN, and Yahoo Chat, it originated in the 70s and 80s, which predates the Internet. Instant Messaging was originally conceptualized as a peer-to-peer protocol that was meant for users to communicate on a network of computers. Shortly after, in the early 80s, the idea of talker systems arose as people begun to log-in to private networks to communicate within a small community. Furthermore, the first primitive internet service Quantum Link was also born, which provided a text-based system called PETSCII on a modem, where people could message each other. In the late 80s, the application called Internet Relay Chat (IRC), developed as users were then able to talk to each other in channels as well as sending private messages to one another.
The New Age
The 1990’s marked an important decade where several Instant Messaging clients first arose. ICQ began in 1996 and was the first IM client to be used by a wide audience. Next, Quantum Leap evolved into America Online, which led to the development of the famous AIM in 1997. As a result of AIM, other companies began to follow suit by launching their own clients. Yahoo!, MSN, and later Google in 2005 launched their own Instant Messenger clients as companies realized that this was a hot, growing field that could add a lot of functionality to their e-mail clients with integration. Today, e-mail clients are almost always paired up with some form of instant messaging client as companies hope this will increase the usage and popularity of their e-mail clients.
In 2000, an application named Jabber, revolutionized the Instant Messaging world as users were able to utilize a single application that is a multi-protocol tool; which allowed a user to simultaneously chat with friends on various messengers. As a result, users no longer had to log into various messaging clients in order to contact friends from that specific client, which saved a lot time and hassle. Today, various other popular multi-protocol applications include Meebo, Trillian, and Pidgin.
Such web applications as Facebook have also realized the advantages of Instant Messaging as it recently redesigned its layout to have its chat system in a more prominent place. Previously, the chat feature was hidden into the lower status bar of Facebook and was not often used. Now, the chat status is located on left navigation page of the home page and users are able to see which of their best friends are online.
Not only has Instant Messaging taken storm within every day use, it also has been integrated into the workplace as employees rely on it heavily now. Such companies as Microsoft have created such products as Microsoft Office Communicator where it contains a wide range of functionality such as chatting, video conferencing, file sharing, and application sharing; while integrating with Microsoft Outlook. Instant Messaging has changed multiple work processes in the enterprise as people are able to accomplish tasks faster and more efficiently. In addition, employees are able to view the current statuses of their fellow co-workers to see if they are at their desk, rather than calling them or sending an e-mail to check. Finally, employees are also able to share documents more easily and able to collaborate on projects more efficiently across the globe.
As Instant Messaging continues to grow, more and more functionality is continuously being added to each application making it a very modular market. Furthermore, as more clients begin to develop, companies will continue to try to consolidate and integrate all the functionalities of various platforms into a central location. As the years continue to pass, Instant Messaging will continue to have a great online presence in the marketplace, but also will continue to develop on other electronic devices such as PDA’s and cell-phones.
Power of eBay
“Just get it on eBay!” This is what my dad said when I couldn’t find cheap enough headphones at the store. It makes me wonder how it all started. Who suddenly woke up one day and decided to invent an online marketplace? A place where people across states, countries can a
uction their used, semi-destroyed items and actually get some money back? Well whoever did (his name is Pierre Omidyar by the way, more on him later…) created a phenomenon, and has revolutionized the meaning of a marketplace through using the Internet.
The start of eBay
The online auction website was founded in San Jose, California, in September 1995 by Pierre Omidyar. He decided on this idea of an online marketplace and went ahead and created a simple program for it. Once he did he put up an ad for a broken laser pointer, and someone actually bought it for $14.83. Astonished, he contacted the buyer and asked them why they bought it, and the buyer explained, “I’m a collector of broken lasers.” This spurred the idea of creating a marketplace for the sale of goods and services for individuals.
In 1998, Pierre and his cofounder Jeff Skoll brought in Meg Whitman to sustain the success. Meg created an experienced management team with an average of 20 years of business experience and built a strong vision for the company -- that eBay is a company that's in the business of connecting people, not selling them things.
They quickly shed the image of only auctioning collectibles and moved into an array of upscale markets where the average sale price (ASP) is higher. ASP is a key metric in determining eBay's transaction fees, so increasing the ASP became an important item. By forging partnerships with namebrands such as GM, Disney and Sun, eBay has managed to do exactly that. Sun has sold $10 million worth of equipment and it now lists between 20 and 150 items per day.
The business model
In simple terms eBay has streamlined the person-to-person trading with their web interface. How? By allowing buyers and sellers to collaborate in a manner where sellers are permitted to list itemsfor sale and buyers bid on items of interest and all eBay users can browse through listed items in an automated way. Now knowing how eBay works, the question is how is it profitable?
Though browsing and bidding on auctions is free of charge, sellers are charged. For one, if an item is listed a non-refundable fee is charged which ranges between 30 cents and $3.30. A second fee is if the seller wants to promote the item, like advertising or changing the style of the item that is displayed, an additional fee is charged. A third and final fee is the end of the seller’s auction.
eBay notifies the buyer and seller via email once the costs are below the minimum price. The binding contract of the auction is between the winner bidder and seller only.
eBay and adversity
How does eBay keep its users? What is their pull? For one, the application itself is definitely a plus point. But the other point is the user trust that eBay has built. Since eBay at no point is directly in the exchange of the item between the seller and buyer, it is hard to build the trust. For eBay to be able to convince users to participate, they must deal with the inevitable delay between the buyer buying the item and receiving it, which is not an issue in the tradition model.
eBay introduced Feedback Forums. At the completion of a transaction, users are encouraged to submit compliments or criticism to the trading profile of the trading partner to the Feedback Forum. By looking at the trading partners history of trades, the user will be able to estimate more accurately the trustworthiness of the trading partner.
eBay and competition
eMay’s idea could easily be copied and these industries did just that: Yahoo and Amazon. Amazon in partnership with the well known auctioneer Sotheby's.
These (and many other) competitors have not only longer operating histories, but larger customer base and greater brand recognition. So why does eBay currenly control more than 80% of the online auction market, with Yahoo and Amazon lagging far behind?
eBay utilized their first mover advantage admirably, quickly and constantly building a community of buyers and sellers.The network effect is important in this market, since the number of buyers and sellers increases the value of the service for other buyers and sellers. If eBay remains price competitive with its competitors there is minimal incentive for the users to switch between auction sites, meaning it becomes more and more difficult for a competitor to displace eBay's trading community.
A different kind of threat is not a direct competitor but a service which can act as a substitute to auctioning, of which Half.com is a good example. Half.com designed a site which allows people to sell used books, music, movies and games at a fixed price. eBay dealt with that threat by buying the company and experimenting with adding their own fixed-price option to their auction listings.
eBay and Future
eBay has become an online middleman for buyers and sellers in a way which traditional brick and mortar companies cannot touch. Using the web has also brought along with it some challenges, especially regarding trust issues between buyers and sellers. eBay seems to have dealt adequately with those trust issues, since users don't seem to mind and continue to use their service.
eBay is operationally sound, especially considering it is still in its buildup period and it has a business model that scales extremely well. The management has shown that it responds quickly and well, and has been working hard to expand the business without jeopardizing the core business.
Wednesday, March 24, 2010
Virus is a small piece of software that piggybacks on real programs to interfere with the normal functions of the machine. It has the ability to damage various programs, overwrite and delete files, reformat hard drives and perform other harmful operations. For example, it can attach itself to a spreadsheet program and each time the program runs, the virus will run and reproduce by attaching to other programs. To be a computer virus…
1. It should be able to execute itself by inserting its code in the execution path of another application.
2. It must be able to self replicate by replacing existing files with copies of infected files.
Virus started because of the spread of PCs, use of computer bulletin boards, and the use of floppy disk. The first computer virus, “Brain Virus” was created in 1986 by two Pakistani brothers, Amjad and Basit Farooq Alvi. This virus, which spread by floppy disks, was known only to infect boot records and not computer hard drives like most viruses today
What Viruses DON’T do
* Viruses do not infect compressed files, unless the file was infected prior to the compression.
* Viruses do not infect computer hardware, such as monitors or computer chips; they only infect software.
* Macintosh viruses do not infect DOS / Window computer software and vice versa. For example, the Melissa virus and the ILOVEYOU virus worked only on Windows based machines and could not operate on Macintosh computers.
Virus vs. Worms vs. Trojan Horses
* Trojan Horses
- Worm is a small piece of software that uses computer networks and security holes to replicate itself from machine to machine. It uses up computer time and network bandwidth when they replicate.
- Unlike a virus, the computer worm does not require a host file in order to propagate itself. It is able to enter a computer through system vulnerabilities and uses those flaws to propagate.
Types of Viruses
1. E-mail Viruses: An email virus travels as an attachment to email messages. It usually replicates itself by automatically mailing itself to dozens of people in the victim’s address book.
2. Boot Sector viruses: It infects diskettes and hard drives and it has ability to hide in boot sector. Boot is the first sector of sectors, smaller sections of disks and hard drives. If you re-boot your computer while the infected disk is in the drive, your hard drive and diskettes can become infected. They were spread when floppy disk was popular since many of them can only spread through floppy disks.
3. Program viruses: It makes copies and will infect other programs on the computer such as .BIN, .COM, .EXE, .OVL, .DRV.
4. Multipartite: It is a hybrid of Boot Sector and Program viruses that infects program files and when the infected program is active, it will affect the boot record. Therefore, the next time you start your computer, it will infect your local drive and other programs
* Some other computer viruses include Macro, Stealth, Active X and Java Control, Polymorphic, Companion, Encrypted, Logic Bomb, Non/Resident viruses.
How to prevent viruses
There are few ways to prevent viruses. You can use more secure operating system like UNIX. Microsoft software is targeted by virus because of their desktop dominance and is criticized for having many errors and holes for viruses. That is why there are relatively few security exploits targeting Mac OS X and is a safer operating system.
Another way is to buy virus protection software. Anti-virus software such as McAfee, Symantec, Kapersky is recommended to keep viruses away from your system and to eradicate them as well. These software include sophisticated scanners that do a quick search of your entire system and detect malicious content from viruses to spyware.
In order for a virus to be effective, there needs to be some action on the user’s part. Therefore, you should avoid programs from unknown sources, but use commercial software purchased on CDs instead. Also, you should never double-click on an unknown email attachment that contains an executable file such as .EXE, .COM, .VBS, and even .JPG. In addition, you should enable Macro Virus Protection in all Microsoft applications which help to prevent many of the email viruses.
Examples of Viruses
* Melissa virus: This virus took advantage of programming language built into Microsoft Word called VBA (Visual Basic for Applications), which uses auto-execute feature. So anyone who downloaded and opened the Word document on the Internet newsgroup triggered the virus. The virus sent the infected documents to first 50 people in the address book which forced Microsoft and other very large companies to completely turn off their email systems until the virus could be contained in March 1999.
* ILOVEYOU virus: Created in the Philippines on May 4, 2000, the virus was sent through email and spread around the world in one day infecting 10 percent of computers connected to the Internet, causing $ 5.5 billion dollars in damage. Anyone who double-clicked on the attachment on the email launched the code and sent copies to everyone in the address book and start corrupting files on the victim’s machine. It was more like Trojan horse distributed by email.
* Code Red: Launched in 2001, it targeted Windows’ IIS servers. It could clog the Internet so effectively that things would completely grind to a halt. It replicated itself for the first 20 days of each month and replaced web pages on infected servers with a page featuring the message “Hacked by Chinese”.
* Slammer worm: In January 2003, it used a hole in Microsoft’s SQL server to infect users.
Monday, March 22, 2010
In case you don’t know the different between an e-book and an e-Reader, an “e-book” generally refers to the text file or pdf version of a book, while an e-Reader usually means a hardware or software device.
The e-book market is huge, and growing rapidly--it is a $350,000,000 market, and increased by 500% between 2002 and 2009. As of September 1, 2009, it was largely dominated by Amazon and Sony; the Kindle had 45% of the market share, while the Sony e-Reader had 30%. There are a number of other e-Readers, however, including the Barnes and Nobles Nook. In addition, Barnes and Nobles and Plastic Logic are developing a new proReader called Que that should be available this summer, while the Apple iPad will be launched in early April. Both the Que and the iPad are not marketing exclusively as e-Readers, while the Kindle, Sony e-Reader, and Nook are primarily e-Readers.
The Kindle, Sony e-Reader, and Nook are primarily used as e-Readers, and allow users to access the internet to download books. The Que is marketed towards mobile business professionals who do not want to worry about carrying a number of important documents around with them, but it also functions as an e-Reader. The iPad performs a number of different functions, which are all listed here; the list includes allowing users to download e-books, and also has the added usability feature that users can “flip” a page and pick their books from a digital bookshelf.
Kindle and Sony e-Reader users can utilize a 3G network to download books, while the Que, Nook, and iPad both have wi-fi or 3G options. The Kindle, Sony e-Reader, and iPad both don’t charge the user for internet access with a monthly bill, but include the cost instead in the price of e-books, and it is likely that Que will also use this model. Most of the e-Readers allow users to browse the internet and check e-mail in addition to just using the device as an e-Reader.
One major different between e-Readers is whether they operate on an open or a closed standard. The Kindle operates on a closed standard, which means that books that you purchase on the Kindle can only be read on select devices. The Nook operates an open system, and so books purchased on the Nook can be read on any device, such as a blackberry. The Kindle achieves a closed system because it uses a specific file format that other devices are unable to read, while the iPad will use technology similar to the iTunes closed standard.
EPUB File Format
E-books come in a variety of different file formats, but .epub has become the standard since September 2007. However, many e-Readers support other file formats, including .pdf, .txt, or .doc files. Before EPUB, e-books used the Open E-book Publication Structure, which consisted of a zip file and a manifest file (a metadata file) and used XHTML and CSS.
EPUB is also similar to a zip file, for it is a compressed file that contains a mimetype, META-INF folder, and OEBPS folder. The mimetype merely tells the e-Reader what it in the EPUB file, and the META-INF folder has an XML file that tells the device where the book is in the file. The OEBPS folder, or packaging files, contain the actual book, including separate folders for images, a table of contents, and another file that contains information like the name of the book and the author, as well as the order that the chapters are supposed to go in.
EPUB is designed so that it contains “reflowable” content, which means that the content will wrap the text based upon the device and the reader’s window size. It also can be used on a number of different devices, and there is no fee to use it. It can contain DRM, is styled with CSS, and contains XHTML.
There are a couple of criticisms of EPUB, including that it doesn’t allow for complex layouts (such as a comic book layout) and also doesn’t have a specific way of annotating books. Including the ability to contain DRM information also negates the idea that the file format is open and can be used on any device.
The Publishing Industry
E-books have substantially changed the publishing industry in a number of different ways. Books that are in the public domain are now much cheaper to produce, and can often times be free (books the public domain are books whose copyright has expired). In addition, the hierarchical structure of the book publishing industry can be skipped by some authors, who can self-publish their books for extremely cheap (although they will not benefit from marketing and networking that an agent and publishing company would provide). In addition, book designers are posed with a number of differences between reading on paper and reading on screens. Royalties also need to be re-negotiated, for before publishers received a larger portion of the profit in order to pay for manufacturing and shipping costs.
Most publishers have embraced the revolution, and some are even using the EPUB file extension in-house in place of their old systems.