
Anthony Weiner —
Anthony Weiner was a hotshot U.S. congressman from New York until he acknowledged tweeting photos of his, ahem, private parts to a woman who was not his wife. He resigned in disgrace in June 2011.

Kelly Oxford —
Kelly Oxford was an unknown Canadian mom before her witty Twitter musings earned her 450,000 followers, praise from Roger Ebert and an offer to write a TV pilot. Her first book comes out next month.

Sohaib Athar —
Sohaib Athar, a computer consultant from Abbottabad, Pakistan, unknowingly live-tweeted part of the May 2011 U.S. raid that killed Osama bin Laden.

Paraskevi Papachristou —
Greek triple jumper Paraskevi Papachristou was banned from the 2012 London Olympics and suspended from her country's Olympic team for an offensive post on Twitter.