Webster's New World Dictionary word of the year: overshare.
overshare (verb): to divulge excessive personal information, as in a blog or broadcast interview, prompting reactions ranging from alarmed discomfort to approval.
Read Ben Zimmer's post at Word Routes.
I usually hear the noun as in 'That was an overshare.' The concept has been around since the invention of taboos and etiquette. I remember little Rob Schneider's bit about oversharing from his stand-up act in the 80s. Specifically his set on the 13th annual Young Comedians Special on HBO. Schneider didn't use the word overshare, but he told a joke about admitting way too much. Something about admitting having killed someone. It was too obvious a line. Not worth quoting now.
I've always thought Fred Stoller had the most memorable set.† Especially his bit about not finishing college.
You know what my mother bothers me about the most? Um—few years ago I quit college. She's always going When are you gonna go back, get your degree?
I go What for? What's it gonna do for me?
This is her reason: she goes You'll be able to say you're a college graduate.
Like I'm not able to say it now? What? Like I try, I go I'm a kaa gegagaweh! I'm a college gegagawah! Damn. Four credits short. I almost had it.
Since then college gegagawah has been an active part of my vocabulary.
† Stoller later had an appearance on Seinfeld as Fred Yerkes, the guy that didn't recognize Elaine, but who easily remembered other details of their meeting: 'The bathroom door. I remember someone had played tic-tac-toe on it, and the Xs won; they went diagonally from the top left to the bottom right.' He also played Cousin Gerard on Everybody Loves Raymond.