Sorry for the noob question.
This is facebook's onion url - facebookcorewwwi.onion
If people want to use facebook anonymously, they can just use facebook with their tor browser right? Why does facebook have to have a onion site? My idea is only if fb want hide themselves, they should be having an onion site. But it is said that fb is running tor hidden service to give users anonymity. I don't undertand how the fb hidden service improves user's anonymity?