Clean up an opt-in email address list

Solution 1:

My question is, how can we send out email to 50k recipients without getting the server blacklisted?

Basically, you can't guarantee it at all. Blacklisting is at the whim of capricious and unaccountable self-appointed blacklist operators - if automated services decide it's spam, or recipients report it as spam, then you can end up on blacklists (whether or not it actually is spam, and whether or not you've sent similar to them before without problems).

The thing to do if that happens is to check on services which test many blacklists and see if you are on them, e.g.

http://www.anti-abuse.org/multi-rbl-check/

http://www.mxtoolbox.com/blacklists.aspx

Then follow the blacklist "how to remove yourself" instructions, if they have them.

You have considered the main things with valid SPF and so on - one other thing you could do is add a contact entry for yourself to http://abuse.net/ - oh and in your preliminary cleaning up checks, as well as making sure the domain exists in the DNS check, also test if it has MX records set and if they are contactable.

I don't really agree with bulk marketing email, but I also don't fully agree with IP blacklisting as currently practised either. It's not a great system for anyone, so just do what you can to make sure the list is clean and honest, and you follow up abuse reports politely, and if one of their lesser uses IPs ends up stuck on some blacklists for a while, well... it's not the end of the world.

Solution 2:

it would be best to batch these into much smaller numbers and send out shots over a 24 hour period. use multiple mail-servers on different domain blocks if need be. all the actions you mentioned should be taken too as they will enable you to be tracked and thus less suspicious.

"some point" - how long ago was the opt in? start with the latest year and check those for continued opt-in first, then each year back.

be aware though: if lots of folks on that list already complained about SPAM, sending them more - even to check if they still want to be on the list is very bad form indeed.