(Noun) Side-effects or secondary consequences resulting from a controverisal post you make on Facebook.
Dude #1: Hey, did you see that self-deprecating Facebook post made by Kara?
Dude #2: I did, what a nut!
Dude #1: Boy I really wanted to go off on her and comment but I didn't want to deal with the Facebook fallout!
The ridiculous amount of notifications and messages recieved after any social event
JEff: 'Awesome party last night, you should have come'
STEVE: 'yeah but look who's wading through the facebook fallout now'