I forwarded mail from my spam-collection domain to new accounts at Yahoo, Hotmail, and Gmail. Yahoo and Hotmail didn’t allow any spam at all to get into the Inbox. Of course, Hotmail had an easier time since they only accepted 926 messages, while Yahoo accepted 4,149. Gmail accepted 3,068, allowing 224 (7.30%) into the Inbox. So maybe Yahoo’s Mail is the webmail system to use. They aren’t flat out dropping as many messages as Gmail, or as Hotmail. It would be really ncie to know what criteria Hotmail and Gmail (and maybe even Yahoo) are using to decide which messages to drop. Is it a blacklist based on message headers? Or based on links in the body? Content analysis (ala spamAssassin)?
Once I noticed that the webmail companies were dropping some mail I stopped the forwarding. Ideally, I should download the mail to my Mac so I can see which messges were dropped. Anyone know a way to easily look for duplicate messages? If I add a X-trace-tag header when the message leaves my doamin, would that invalidate the header trail?