Most times when someone joins a forum and doesn't post, they're just leaving link spam on the forum profile. And, I've heard some spammers try to justify saying at least they're not spamming open forum. But your Google adsense account can get shut down if those spammers are linking to illegal websites. So it pays to police your profile pages. Most times, I delete profile pages of members who never post. Also, I have a mod that does not allow any signature links for members under a certain post count. That doesn't stop them from posting a link on the profile page. So if they don't post after a certain time, their account gets deleted. How do you handle profile page spam?