Content is considered appropriate enough to be viewed by the general public of the facebook community i.e friends/significant others/family/coworkers without having to worry about explaining a sketchy situation
The gremlin that attacks your Facebook account and makes your posts appear multiple times. This also explains the other strange aspects to Facebook such as virtual gifts that have no value and randomly poking people - things that just don't make sense.
Friend (posted in comments): Okay then, I'll see you tonight.
Friend (posted in comments): Okay then, I'll see you tonight.
You (posted in comments): Oh no, you've been attacked by the Facebookalich. Turn off the computer NOW!
when someone's name is common enough to look up on facebook easily and find them.
Michelle Johnson vs. Michelle Jawnsun. Michelle Jawnsun would be a name that you could put in facebookand find the person easily that you are looking for because their spelling is a bit odd. Michelle Johnson is too common to be facebookable because too many people share that name it is harder to find that person.