Flashbooking
A mash-up of "flashback" and "Facebooking." Occurs when a friend likes/comments on an embarrassing Facebook status or photo from many years ago, causing it to go to everyone's newsfeed, thus making the person ashamed of their stupidity/awful haircut/mirror selfie.
Erica was Flashbooking last night and got me good. I forgot I still had those selfie's from high school bandcamp on my Facebook.