I didn’t used to think so.  In fact, I used to use MAPS and other lists on my mailserver(s) – still do actually, even for clients.  I do, however, think that some of the new blacklists regarding optin/optout and other rules that they’re pushing are simply a bit too far.  It will be interesting to see how this evolves over the next year.  Are SPAM Blacklists Unreasonable? [Slashdot]