This is a good tool as well:http://senderid.returnpath.net/how.phpChecks the following:SPF MethodDomainKeySender ID MFROM MethodSender ID PRA MethodExplanation of Results:"MAIL FROM" shows the email address in the MAIL FROM (Return Path) header of yo...

Checking for records - that I personally know of:DKs:Yahoo (all partners)GmailSender ID/SPF:AOLHotmail/MSNGmailThis covers 60+ million email addresses between the 5 of them.Would not surprise me to see more MAAWG members start checking DKs once they ...

For those out there that are considering DK's you should know that Yahoo! and their partner domains (ex. SBC/Rogers.com) are now publishing the fact that you are authenticating in their user interfaces.Authentication-Results: mta114.mail.scd.yahoo.co...