On one of my free mainstream sites i have a ton of members and sending out any type of newsletter is a nightmare. Due to the amount of members and emails that we send out - Using another service to send them out such as aweber would cost an arm and a leg. Thus we been sending out emails from our own servers. We are using DKIM.
Most of our emails is going out to gmail/aol/yahoo and msn. We don't seem to have too many issues with gmail/msn but aol and yahoo will occasionally defer our email messages.
We haven't able to get whitelisted at yahoo or aol.
Curious if anyone is using
http://www.certifiedemail.net/ or returnpath?