This category contains sites that maintain spam blacklists. Some of these blacklists are services that can be used to filter e-mail, and other blacklists are simply lists of spam-friendly ISP's and companies. Blacklists are distinct from spam filters; blacklists provide information about known spammers, but do not by themselves prevent spam from being received. Filters are programs that prevent a user from seeing spam (possibly by using a blacklist.)
A listing of blacklist organizations. Contact these organizations directly to use or make inquiries about their blacklists.