> - You need to make sure that your email servers IPs are not on black lists.
This alone is a huge, huge chore. Especially if you run a hosted service that allows some user-specified content in outbound email bodies. It's a lot cheaper for us to pay Mandrill to handle all of that for us, provide us excellent metrics and diagnostics, and let us know if one of our users is sending junk mail before it gets out of hand.
Well, we have been put on blacklists that the operator wanted money to "expedite" removal from. I'm assuming that blacklist was pretty much random IPs... And it did impact deliverability.
This alone is a huge, huge chore. Especially if you run a hosted service that allows some user-specified content in outbound email bodies. It's a lot cheaper for us to pay Mandrill to handle all of that for us, provide us excellent metrics and diagnostics, and let us know if one of our users is sending junk mail before it gets out of hand.