The first blog was launched in 1997. A blog is an online diary kept by a person or a group, usually in reverse chronological order, and can be updated every minute or once a month. There were 14 million blogs worldwide in July 2005, with 80,000 new blogs per day. According to Technorati, the first blog search engine, there were 65 million blogs in December 2006, with 175,000 new blogs per day. Some blogs are devoted to photos (photoblogs), music (audioblogs or podcasts), and videos (vlogs or videoblogs). The wiki concept became quite popular in 2000. Deriving from the Hawaiian term "wiki" ("fast"), a wiki is a website allowing multiple users to collaborate online on the same project. Users can contribute to drafting content, editing it, improving it, and updating it. The software can be simple or more elaborate. A simple program handles text and hyperlinks. With a more elaborate program, one can embed images, charts, tables, etc. The most famous wiki is Wikipedia. Facebook was founded in February 2004 by Mark Zuckerberg and his fellow students as a social network. Originally created for the students of Harvard University, it was then available to students from any university in the U.S. before being open to anyone worldwide in September 2006, to connect with relatives, friends and strangers. Facebook was the second most visited website after Google, with 500 million users in June 2010, while sparking debates on privacy issues. Founded in 2006 by Jack Dorsey and Biz Stone, Twitter is a social networking and micro-blogging tool to send free short messages of 140 characters maximum, called tweets, via the internet, IM or SMS. Sometimes described as the SMS of the internet, Twitter gained worldwide popularity, with 106 million users in April 2010, and 300,000 new users per day. As for tweets, there were 5,000 per day in 2007, 300,000 in 2008, 2.5 million in 2009, 50 million in January 2010, and 55 million in April 2010, with the archiving of public tweets by the Library of Congress as a reflection of the trends of our time. We now try to fullfill the second part of Tim Berners-Lee’s dream, according to his essay dated April 1998: “There was a second part of the dream, too, dependent on the web being so generally used that it became a realistic mirror (or in fact the primary embodiment) of the ways in which we work and play and socialize. That was that once the state of our interactions was online, we could then use computers to help us analyze it, make sense of what we are doing, where we individually fit in, and how we can better work together." 2005 > FROM PDAS TO SMARTPHONES