Dear Email Diva,
I've created and run a couple different widely used blacklists over the years (including the MAPS RSS), and helped out with others. I also run a Web site at http://www.dnsbl.com where I track blacklist usage, and provide blacklist reviews and status information.
[To update your list of blacklist compilers and services from last week:] First, Ironport owns Spamcop. Spamcop is the name for Ironport's blacklist and spam reporting service. So, Ironport isn't a blacklist on its own. It's not a bad idea to check SenderBase, but it's not a blacklist.
Second, SPEWS has been frozen in time, broken or abandoned for many months. I detailed this on my Web site back in January, 2007. Visit http://www.dnsbl.com/2007/01/spews-current-status.html for more info. As a result, SPEWS isn't used for blocking any more, and it's not one of the blacklists somebody needs to worry about. A list called APEWS has tried to take its place, though it also is not widely used, has very broad/inaccurate listing criteria, and is not something to be concerned about.
MAPS is the old school king of the blacklists -- or rather, it was. It's not any more. Its lists are now available for pay use only, and have been this way since (I believe) 2001. The result is that the wide usage of the MAPS lists (when I worked for MAPS in 2000 we estimated that 40% of your mail would bounce if you were blacklisted by MAPS) has greatly diminished and you don't really run into it nowadays. A few ISPs, like RoadRunner, use it, but I don't recall the last time I actually ran into somebody with a MAPS listing issue. It's definitely not the first place to check when looking to see if you've got a big, bad blacklisting issue.
Spamhaus has really taken the place as the leader at the forefront of the spam blacklist movement. Though there are ongoing legal battles between Spamhaus and a company called E360, their lists are still widely used and anybody on the business end of a Spamhaus listing will find significant negative deliverability issues as a result. My own testing shows that the Spamhaus lists are very accurate, block much spam, while very rarely (if ever) impacting legitimate mail, and I suspect many large ISPs use the Spamhaus lists for this very reason.
Other lists that are used less often but may still impact your ability to deliver mail are NJABL and SORBS. NJABL =--- "Not Just Another Bogus List" -- is usually known for being responsibly run and is used by a significant number of sites to block mail. SORBS is a more aggressively run list from Australia. It may not always be easy to resolve a SORBS listing. These are the ones I'd recommend checking, as far as IP-based blacklists (DNSBLs) are concerned.
I'd also recommend checking your "from" domain CORRECT? From domain?, bounce domain, image link and redirector domains on the two Domain/URL based blacklists: SURBL and URIBL. You can check both of those here: http://www.rulesemporium.com/cgi-bin/uribl.cgi
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.
Anybody working with an ESP to send their mail should ask their ESP what they are doing to monitor, discover, and resolve blacklist issues. Not everybody knows what they're doing on this front, if I do say so myself!
Director, Privacy and Deliverability, ExactTarget
Thank you for this very helpful, very thorough information.
The Email Diva
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