During our previous attacks, some SingNet users were inadvertently blocked as part of our mitigation. It turns out that some ISPs give the users a different IPs on every outbound request. You will not get "Your IP has been blocked" messages any more, and we've fixed the problem.
For everyone else,
We have a great suggestions community, but if you could sum it up in a sentence or two, what could we do better? More Twitter posts? Account creation limits? What's the trade off between spam and captchas? Should we make everyone do difficult math problems before posting? :)
EDIT: We're not actually going to limit accounts. The most we might do is limit the rate at wich you can create new accounts, like only a a few per *minute*.