The signup / registration page doesn't cleanse user input. For example, I just signed up with an email address that ended in "berkeley.edui" (because I'm tired). I waited for the confirmation email, realized my error, and went to re-signup. However, the username that I wanted was taken by my ".edui" registration and I had to pick something different that I won't be able to remember. [It's obviously not a big deal, but it does seem like a bug.]

1) If there is an incentive for users to visit this site, it isn't clear to me what it is or how it works. It should be featured prominently on the main page. 2) I couldn't find a forum for students (so I just posted on one for educators). If there is one, it should be more clear. If there isn't one, having one would be very helpful. 3) The "recent changes" section to my left is unhelpful to me. It wasn't immediately clear what its function was, and now that I understand it, its utility doesn't justify its placement on the page.

It's probably just my browser, but the rating icons don't show up for me; they are just broken image links.