Many vb boards have mandatory custom profile fields. Spam bots need to fill these in to register. Every board has different custom fields, so spammers have little chance to anticipate. It would be easy to add invisible fields with standard names. If you add a hidden profile field named 'Interests' then chances are that a bot will recognize this and fill it in. There used to be a addon that did this, but cant find it ATM.
Two other suggestion that would make this anti-spam suite complete are:
- Bad behaviour: http://www.bad-behavior.ioerror.us/d.../how-it-works/
- Option to disallow disposable email domains from registration. There is a list here. People can easily add the list to the email ban list, but it would be far more useful to have a centrally updated list. (doesnt need to be updated more than once every few months) And most admins do not realize the problems that disposable email addresses pose.
BTW: Many boards are getting a lot of profile spam these days. Does this addon deal with that or is that something that needs an additional solution?