Blacklists used to be an email marketer’s worst nightmare. If you made a silly mistake and got blacklisted, good luck convincing the admin to delist you.
Thankfully, things have become more civil and professional (you still don’t want to get blacklisted though). Here’s an up-to-date assessment of blacklists from Al Iverson.
Iverson speaks the truth:
I would note that if somebody is a B2C sender with an average list composition, then blacklists shouldn’t be your biggest worry. Blocking by the top ISPs (AOL, Hotmail, Yahoo, Juno, Earthlink, etc.) is generally more likely to cause greater issues, or happen more often, than a third-party blacklisting of a sender’s IP address
More worrisome, in my opinion, are the Postinis and Barracudas of the world. Those are increasingly becoming the "gatekeepers" of company email servers, and I don’t see much of an effort on their part to work with legit email marketers and ESPs (such as setting up feedback loops, or registering for alerts like SpamCop). In those cases, it’s just like Iverson says—you better make sure your ESP is on top of things, and is in contact with those groups.
Speaking of blacklists, Seth Godin just posted this page on Squidoo with a good roundup of articles and resources on how to avoid getting blacklisted. Most of the links are to our good friend Mark Brownlow’s blog, but you’ll also find a link—waaaaay down at the bottom—for our Inbox Inspector. Yay, we’ve been Seth’d.