The Celebrity: Michael Beasley
The Infraction: In August 2009, Miami Heat forward Michael Beasley wanted to show off a new tattoo he'd gotten on his back. Cool. Except that when he took the photo and posted it on Twitter.... he forgot that something else was in the picture, too. And that something else was enough to force him to check into a mental hospital. And ruin the start of his NBA career. Yikes!
Lesson Learned: Do a little self-editing before you TwitPic anything. If you don't think people will notice that—yes, that! over there!—they will. And it'll be all over the blogs in T-minus two minutes.