Facebook rejects advertisements it decides are ungrammatical or incorrectly punctuated.
The people who developed that software should pick a fight with the people who write the display copy for the site. We just found this:
Somebody has just compared you to its other friends.
Its other friends? We get that they wanted to avoid somebody+a plural. But "its" isn't right, either. If such a thing is possible, it's probably even more incorrect, even though anybody--and, presumably anything--can get a Facebook account these days.
There are several ways to write around this.
One of your friends has compared you to others.
You've been compared to others.
How do you compare to others? Find out!
Even "somebody has just compared you to their friends" is better than what they've got. How does this happen? It's madness, we say. Madness!