1. A person who constantly brags about his blurry, pseudo-achievements by updating his Facebook status so that others can have an untruthful image of him;
2. A person who takes pictures, or edits them, for the sake of showing off on Facebook.
Mike: Did you see that Jamey was talking about his school grades again on Facebook?
Mickey: Oh, don't even mention that, he's such a facebookoser, I've even blocked him because of that. I'm sick of him trying to get attention for something that is not even real.
Jenny: Have you seen Marry's photos from the beach?
Jessy: I wonder why somebody would post a half-naked picture of herself on the internet, she's such a facebookoser.