Off the top of my head I remember http://www.stopforumspam.com/ http://www.stopforumspam.com/ exists - which is something I use n my on blogspam-detector http:/

Off the top of my head I remember http://www.stopforumspam.com/ http://www.stopforumspam.com/ exists - which is something I use n my on blogspam-detector http://blogspam.net/ http://blogspam.net/ But I suspect that you'd be better placed to look at the patterns yourself, if you were to setup some simple node.js/dancer/service to test an IP/email/name combination and return a "yes/no" result you could then experiment with different metrics. One thing I do on my sites is block IPs. So if bogus-user-bob signs up from 1.2.3.4 then no other user will be permitted to sign up from that IP. I realize that proxies will allow this to blacklist too many remote users, but in practice I haven't had complaints.