Timeline: The Most Important Social-Media Events in History\u000AThe first e-mail was sent just over 40 years ago; we\u0027ve come a long way, baby. But along with the highs (Twitter-enabled revolutions, Chatroulette), there have been a lot of lows (Kim Kardashian\u0027s tweets, Chatroulette). These are the moments that are worth remembering and, in some cases, cringing about. Plus: See our complete coverage of social media mavericks.\u000A1971: The first e-mail travels between two computers one meter apart. Many coworkers continue to communicate this way—rather than actually talking.\u000A\u000ACredit: Getty Images\u000A1979: Online services enter the scene, starting with CompuServe (1979), AOL (1983), and Prodigy (1984).\u000A\u000A1980: The first dedicated chat room, CompuServe\u0027s CB Simulator, launches. Yes, as in CB radio.\u000A\u000ACredit: AP\u000A1994: Anyone can make a website with Yahoo! GeoCities. (The service closed down in 2009.)\u000A\u000ACredit: Newscom\u000A1995: Classmates.com emerges as a way to keep up with old high-school buddies. You probably saw the ads (\u0022She married him?\u0022 \u0022She\u0027s a model now?\u0022).\u000A\u000ASee also: Memory Lane.\u000A1997: AOL Instant Messenger kills the chat room. Creepy middle-aged dudes everywhere mourn the loss.\u000A\u000A1999: Anyone can blog! Open Diary, LiveJournal, and Blogger.com all launch at around the same time.\u000A\u000ACourtesy of Flickr/jesseproper\u000AMarch 2002: About 3 million people join Friendster during its first three months. But what to do with it once you have an account?\u000A\u000ACourtesy of Flickr/ajkandy\u000AMay 2003: With very little fanfare, LinkedIn arrives on the scene.\u000A\u000ACredit: Getty Images\u000ASeptember 2003: Myspace debuts with tons of customization tools that reveal the terrible design sensibility of the average person.\u000A\u000ACourtesy of Gizmodo\u000AFebruary 2004: Mark Zuckerberg, the Harvard dropout with the Adidas shower sandals, follows up his success with Facemash (think: Hot or Not) by launching Facebook. Six years later, he\u0027s king of the world.\u000A\u000AAlso: Flickr launches.\u000A\u000ACredit: AP\u000ADecember 2005: \u0022Lazy Sunday,\u0022 a music video featuring Andy Samberg and fellow cast member Chris Parnell is broadcast on Saturday Night Live and then goes viral. Going viral becomes a thing.\u000AMarch 2006: Blogs are deemed too long. Twitter sets the new upper limit: 140 characters.\u000A\u000ADecember 2006: Yahoo makes a billion-dollar bid for Facebook. No deal.\u000A\u000ACredit: AP\u000AJanuary 2007: Justin Bieber posts his first video—a shadowy Ne-Yo cover shot in a school auditorium—to YouTube. A gazillion views and counting.\u000AFebruary 2007: Twenty-year-old founder David Karp bills Tumblr as a blog for the lazy: \u0022a fabulous alternative to the 90 percent of Web users who don\u0027t care to maintain a blog,\u0022 he posts to WordPress.\u000A\u000ACourtesy of Flickr/parawendolyne\u000AJuly 2007: Regular folk submit questions for the candidates during the CNN-YouTube presidential debates. Anderson Cooper moderates.\u000A\u000ACredit: Getty Images\u000AApril 2008: Facebook\u0027s traffic overtakes that of Myspace, which goes from being a massive social network to a place for bands to get the word out.\u000A\u000ACredit: Getty Images\u000AMarch 2009: The world gets thousands more mayors, thanks to Foursquare. And badges. Suddenly everyone wants a badge.\u000AFebruary 2010: Rumors suggest that Kim Kardashian earns $10,000 per endorsement tweet.\u000A\u000ACredit: AP\u000AMarch 2010: Facebook beats out Google as the most trafficked site on the Internet.\u000A\u000AOctober 2010: Instagram launches.\u000A\u000ACredit: Getty Images\u000AMay 2011: LinkedIn has a famous initial public offering (IPO). Share prices more than double, and words like bubble and frothy market are bandied about.\u000A\u000ACredit: AP\u000AJune 2011: The masses learn the difference between a tweet and a direct message thanks to Anthony Weiner.\u000A\u000AGoogle+ launches.\u000A\u000AJustin Timberlake (perhaps inspired by his role as an Internet mogul in The Social Network) and Specific Media acquire Myspace for $35 million—$545 million less than News Corporation paid for it in 2005.\u000A\u000ACredit: AP\u000AAugust 2011: Details magazine publishes \u0022The Social Issue,\u0022 guest edited by Ashton Kutcher. Okay, well, it was important to us.\u000A\u000ANovember 2011: After a Joe Paterno-related flub on Twitter, Ashton Kutcher hands over the keys to @aplusk to his team. Twitter will never be the same.\u000A\u000ACredit: Corbis\u000AJanuary 2012: Google+ hits the 90-million-user mark and—experts predict—is on track to reach 400 million users by the end of the year, which would make it half the size of Facebook.