Facebook

Features
Main article: Facebook features
The media often compares Facebook to MySpace, but one significant difference between the two websites is the level of customization.[32] MySpace allows users to decorate their profiles using HTML and Cascading Style Sheets (CSS), while Facebook only allows plain text.[33]

Facebook has a number of features for users to interact with. They include the Wall, a space on every user's profile page that allows friends to post messages for the user to see,[34] Pokes, which allows users to send a virtual "poke" to each other (a notification that tells a user that they have been poked),[35] Photos, where users can upload albums and photos,[36] and Status, which allows users to inform their friends of their whereabouts and actions.[37] A user's Wall is visible to anyone who is able to see that user's profile, which depends on their privacy settings. In July 2007, Facebook began allowing users to post attachments to the Wall, whereas the Wall was previously limited to textual content only.[34]

Over time, Facebook has added several new features to its website. On September 6, 2006, a News Feed was announced, which appears on every user's homepage and highlights information including profile changes, upcoming events, and birthdays related to the user's friends.[38] Initially, the News Feed caused dissatisfaction among Facebook users; some complained it was too cluttered and full of undesired information, while others were concerned it made it too easy for other people to track down individual activities (such as changes in relationship status, events, and conversations with other users).[39] In response to this dissatisfaction, Zuckerberg issued an apology for the site's failure to include appropriate customizable privacy features.[40] Since then, users have been able to control what types of information are shared automatically with friends.[40] Users are now able to prevent friends from seeing updates about different types of activities, including profile changes, Wall posts, and newly added friends.[40]

One of the most popular applications on Facebook is the Photos application, where users can upload albums and photos.[36] Facebook allows users to upload an unlimited number of photos, compared with other image hosting services such as Photobucket and Flickr, which apply limits to the number of photos that a user is allowed to upload. However, users are limited to 60 photos per album. Privacy settings can be set for individual albums, limiting the groups of users that can see an album. For example, the privacy of an album can be set so that only the user's friends can see the album, while the privacy of another album can be set so that all Facebook users can see it. Another feature of the Photos applications is the ability to "tag", or label users in a photo. For instance, if a photo contains a user's friend, then the user can tag the friend in the photo. This sends a notification to the friend that they have been tagged, and provides them a link to see the photo.[41]

Facebook Notes was introduced on August 22, 2006, a blogging feature that allowed tags and embeddable images. Users were later able to import blogs from Xanga, LiveJournal, Blogger, and other blogging services.[11] During the week of April 7, 2008, Facebook released a Comet-based[42] instant messaging application called "Chat" to several networks,[43] which allows users to communicate with friends and is similar in functionality to desktop-based instant messengers.

Facebook launched Gifts on February 8, 2007, which allows users to send virtual gifts to their friends that appear on the recipient's profile. Gifts cost $1.00 each to purchase, and a personalized message can be attached to each gift.[44][45] On May 14, 2007, Facebook launched Marketplace, which lets users post free classified ads.[46] Marketplace has been compared to Craigslist by CNET, which points out that the major difference between the two is that listings posted by a user on Marketplace are only seen by users that are in the same network as that user, whereas listings posted on Craigslist can be seen by anyone.[47]

Platform
Facebook launched the Facebook Platform on May 24, 2007, providing a framework for software developers to create applications that interact with core Facebook features.[48][49] A markup language called Facebook markup language was introduced simultaneously; it is used to customize the "look and feel" of applications that developers create. Using the Platform, Facebook launched several new applications,[48][49] including Gifts, allowing users to send virtual gifts to each other, Marketplace, allowing users to post free classified ads, Events, giving users a method of informing their friends about upcoming events, and Video, letting users share homemade videos with one another.[50][51]

Applications that have been created on the Platform include chess and Scrabble, both which allow users to play games with their friends.[52][53] These games are asynchronous, meaning that a user's moves are saved on the website, allowing the next move to be made at any time rather than immediately after the previous move.[54] Within a few months of launching the Facebook Platform, issues arose regarding "application spam", which involves Facebook applications "spamming" users to request it be installed.[55] Application spam has been considered one of the possible causes to the drop in visitors to Facebook starting from the beginning of 2008, when its growth had fallen from December 2007 to January 2008, its first drop since its launch in 2004.[56]

Controversy
See also: Criticism of Facebook and Use of social network websites in investigations
Facebook has met with some controversy over the past few years. In October 2005, the University of New Mexico blocked access to Facebook from its campus computers and networks.[57] It cited a violation of the university's Acceptable Use Policy for abusing computer resources as the reason, stating the website forces use of the university's credentials for activity not related to the university. The school later unblocked Facebook after the website rectified the situation by displaying a notice on the login page stating the credentials used on the website are separate from the ones used for their school accounts.[58] The Ontario government also blocked access to Facebook for its employees in May 2007, stating the website was "not directly related to the workplace".[59]

A notable ancillary effect of social networking websites like Facebook is the ability for participants to mourn publicly for a deceased individual. On January 1, 2008, a memorial group on Facebook posted the identity of murdered Toronto teenager Stefanie Rengel, whose family had not yet given the Toronto Police Service their consent to release her name to the media.[60] While police and Facebook staff attempted to comply with the privacy regulations by deleting posts mentioning her name, they noted it was difficult to effectively police individual users who repeatedly republished the deleted information.[61]

Due to the open nature of Facebook, several countries have banned access to it including Syria and Iran.[62][63] The Syrian government cited the ban was on the premise that the website promoted attacks on authorities.[62][64] The government also feared Israeli infiltration of Syrian social networks on Facebook.[62] Facebook was also used by Syrian citizens to criticize the government, and public criticism of the Syrian government is punishable by imprisonment.[62] In Iran, the website was banned because of fears that opposition movements were being organized on the website.[63]