Blacklists and Filtering: The Email Marketer's Best Friends | ClickZ

I often speak with inexperienced email marketers that rail against blacklisting. Many are angry that ISPs have the "right" to divert the commercial electronic messages they send from the inbox, sending them to the junk mail folder or, even more frustrating, to the black hole where email missives go and are never seen again.

Read the rest of this article for insight into why, although they're an obstacle for legitimate email marketers, blacklists and filters exist are at the same time a necessity.