Spam.

how do u stop someone from makin many email accounts and spammin the website with all dif email accounts so how would that stop him from spammin?

I think you can ban the IP

He can use proxies

Easy: If that fails, you put a word censor on their website address. No links to it can be made then, and all existing ones stop working.

That's what CLF does to us
--WetWired

Then I could get some shitty .NoNoNoNoNoNoNoNo direction and spam more, but i wont