Warren Buffett joined Twitter Thursday. Here's a look back at nine other notable first tweets.
After the famous "Tonight Show" conflict between NBC, Jay Leno, and Conan O'Brien, the flame-haired comic aired his last show on January 22, 2010. After his tearful goodbye -- which included an uncharacteristically sincere speech about working hard and avoiding cynicism -- O'Brien laid low for more than a month.
O'Brien re-emerged in February 2010, taking to Twitter to joke about his unemployment. "Coco" gained 78,000 followers in just two hours, according to the LA Times.