A horrible phenomena that was created by a group of college students who were willing to do anything besides study for their exams. The word refers to the process of going back to someone face-book posts in the past and through liking and commenting bringing old status that deserve to stay dead into the present where everyone can then humiliate the original poster for their naivety and general lack of sense.
Mariah: Did you see that post on Charles wall? He said Twilight was awesome!
Erik: Yeah, someone must of 2009-ed him.