People who use the comments section of any social networking site to engage in discussion with others who have commented on a particular photo, status update or other newsworthy item which is totally unrelated to the original post and particularly annoying to everyone else that receives updates of all comments.
Mark: Hey all, did you see the sunset today? It was awesome! Check out this photo.
Tina: Oh man, no, I was stuck in the office.
Geanny: YES! I love California sunsets.
Bill: Hey Geanny, haven't seen you in a while.
Geanny: Oh hey Bill, nice to hear from you, how are you?
Bill: I'm great, the kids are great, my wife recovered from her knee surgery just fine.
Geanny: Oh wonderful to hear, Bill, we should meet up for lunch sometime.
Bill: Great idea Geanny, how does tomorrow sound?
Geanny: How about at Starbucks?
Bill: You mean the one over in Irvine?
Geanny: No Aliso.
Tina: Guys, can you take this conversation offline, I'm in Dallas so I don't need to hear about your coffee date!
Geanny: Oh sorry, I didn't realize that everyone was getting these messages.
Bill's WIFE: Bill who the hell is Geanny?
Bill: Uh oh, I'm in trouble now!
Mark: Haha, that's what you get for being a Comment Jacker!
An event in which somebody nearby had a camera phone, captured a unique and most often embarrassing moment and then promptly uploaded it to their Facebook profile.
Example: Your best friend passed out at a party, so everyone decided to draw pictures on his face and wrap him in saran wrap. Being the good friend that you are, you captured that Facebook Moment by snapping a photo of him on your camera phone and then posted it on your Facebook profile long before your friend woke up.