I could be off, but it looks like you are blocking, or at least not responding, to new user request coming from certain domains. I signed up earlier today using a @yahoo.com email address. I clicked the link numerous times to get another email sent so I could activate my account and I have yet to get a single confirmation email.
Yet, I just created this account using a less generic email provider and I got my email confirmation right away. I did check my spam folder, I did confirm my original email address is correct, just as I know some board moderators do certain things with certain settings, in regards to peculiar email providers hoping to dodge a load of spammer... Though it also keeps genuine customers at bay.
Anyway... Yeah... If you're not blacklisting yahoo.com email, then lets find out why I'm not getting my confirmation email because I'd rather use my other account I created this morning, "blaze_125" instead of this one.