The act of searching for old flames, lovers, flings, crushes, acquaintances, etc. on Facebook while intoxicated, which results in sending friend requests that you wouldn't typically send if you were sober. Very similar to drunk dialing.
I noticed you and Joe are now Facebook friends. How did that happen?
n. The practice of adding large numbers of random people to one's friends list on an online journaling site (e.g, LiveJournal, GreatestJournal, Xanga), often with the intent to annoy the users they friend because the adder's username shows up in their "Friend of" list.
On LiveJournal, users may hide individual users from their "Friend Of" list by banning them in the admin console or hide their entire "Friend Of" list from being displayed by checking the box by "Hide "Friend of" list" when editing their Personal Info.
Creating a LiveJournal account with a potentiallyoffensive name and adding Friends to the limit of 750 within a week of creating the account are hallmarks of serial adding.