This. Anonymous image boards exist as an antithesis to social networking garbage like failbook.
Anonymity allows posts to be looked at for the merit of their content rather than the users' following. There's a reason why many *channers aren't fond of reddit, traditional forums, and other such social sites. Nobody likes everyone's favorite pet winning an arguement based on their e-fame. Nobody likes that one guy who said that one thing that was unpopular being completely blown off even if he makes a compelling arguement. Anonymity also gives a certain level of privacy that allows users to be more honest than they would be in public.
We have sage, failbook has no dislike button. I think quality of users is more important than quantity of users any day. Those who are looking for sites like this one can easily find it. Those who can't, probably wouldn't be comfortable here.