If you tried to sign up, and never received a activation email, please try registering again. I've also cleared all accounts that had not yet been activated, so any registered-but-unactivated usernames should be available now as well.

Basically, the site has been using an ad-hoc system of gmail and other mail hosts for sending activation e-mails, mostly because I've been trying to avoid having to deal with setting up a proper mailing system. I finally gave up and set up a proper mail system, so signup emails should now send somewhat more reliably.