When 2 random kids start a "fight" on facebook after one comments on someone's status and another kid begs to differ so they write how kid#1 is wrong. They then start commenting back and fourth and eventually other kids get involved and add their 2 cents, even though no one really gives a shit. It makes the person whose status it was originally, want to shoot themselves becuase they get 50 notifications via e-mail. Because there are so many comments, these usually show up in the "Top News" feed giving them even more attention. The so-called fight is usually about some insignificant shit that doesn't even really matter. The "fight" doesn't neccesarily have to do with the original status.
Conor: Did you hear Paul and Tom are fighting?
Sam: yeahh, it came up on my newsfeed.
Conor: Whose side are you taking?
Sam: probably Tom's, but its just a facebook fight. It probably wont get carried away.