Third-party filtering services are useful for users who want to have their email filtered before they download it. This is common for users who travel or have slower forms of Internet access. Many filtering services use blacklists and/or content filtering, and bounce messages failing the filtering rules. Because no filter is perfect, eventually valid email will be bounced. Because the user is not notified when emails are bounced, it's up to the sender to try to contact the user by some other means to straighten out the problem.

Some services, though, offer the ability to view messages which the filter regards as spam. Messages are typically stored for a period of time and then automatically deleted. Users view the messages via a Web interface.

Third-party spam filtering services are paid services, and are probably not right for most users. If you need to access your email often via a dialup connection, however, and you get significant amounts of spam, contact us to discuss your needs.