Hmmm.

First thing, I did think like dbskyler - for some people, anonymity is needed to give their honest opinion - you know, not out of intention to offend, but because these things are so sensitive (and let's admit it, out fanfics are our babies! Except for some of my fanfics which I disown...) and they're afraid to mess up friendships if their honest opinion is taken up too well.
OR, the other way round. Afraid people won't give their honest opinion because they would be afraid it would be taken the wrong way. Thing is, I get what you say about anonymity, and in a perfect world you'd be right, but internet fandom in general, not just Who, simply doesn't work that way.

Which leads us to the second part, which is, yes, these reviews are anonymous, but not exactly. I could have set this up with a sock puppet. I could also have let people post their reviews anonymously directly to the comm. It's not by accident all reviews are posted under my username - no, I didn't write all of them, but I, personally, am taking responsibility for any review that's posted through the comm. That's sort of my way of circumnavigating the biggest problem about anonymity (at least the bit I feel is the biggest problem) - the no responsibility bit.

But, of course, you're free to disagree, that's the beauty of the internet. ;)