In the last two weeks, I've sent three emails to AOL regarding emails from a domain that I maintain on a shared host failing to be delivered to email addresses in the AOL.com domain. In my emails I asked if AOL could tell me why the emails where not being delivered and no bounce-back was sent to the sending address.
In response, I received nothing, nada, zilch, zero, zip, null.
People with AOL addresses also asked AOL tech-support why the emails weren't being delivered. The answers received from AOL tech where useless and simply said go to http://postmaster.aol.com/
where honestly, the problem was not addressed.
All AOL needed to say was that the "Return-Path:" in the email header needed to be set to an email address on the originating domain. Because the domain is on a shared host machine, the Return-Path was set to the default sender of the shared-host machine.
So, if you have a site on a shared host, and emails from your site aren't being delivered to people at aol.com, check the Return-Path in your outgoing email headers. If it doesn't contain an email address from your domain, change it.
AOL, I hate you, thanks for nothing.