We've been getting a lot of spam. Sorry. I've added a captcha for all new registrants so that it will hopefully slow down the users who register to spam the site. I've also blocked what I think are the spamming accounts. If I accidentally deleted your account - sorry - re-register and send me a message and I will re-enable the account.
If the spam continues then I'll add captchas to additional parts as well.
Cheers,