Obvious spammers use things like "viagra" and "sex" and "designer handbags" in their interests line. More subtle spammers mention music, biking, etc. (keywords from this site). Google helps me find out which users' emails and sites are associated with spam. I refuse to let spammers join, and delete their accounts.
I also hide the memberlist (which contains links to websites) from everyone but me. This means your profile is only accessible to people if you post. So, it's a little extra privacy for you and (hopefully) less spammer requests for me.
I also removed the website and instant message links from the registration process. We can still add those fields to our profiles once we're registered, but spammers now have nowhere to post links to their sites.
If you are a legitimate user, and I mean someone genuinely interested in posting on here about the music, games, travel, and other topics, then when you register, make sure your Interests field is specific and convincing. That will help me separate the genuine fans from the spammers.
And finally, if you are a legitimate user and find that your account has been deleted, contact me via this link:
http://tripalot.com/contact/
If you're convincing, I'll let you in.
If you babble away about handbags full of viagra and online lotto tickets, then hasta la vista, spammer!