yes, but as someone who's worked on the sending of emails side of this i can assure you that the techniques for fighting spam are TOO effective. There are many legit emails that go into black holes before any standard idea of spam filtering comes into play. I wrote an embeddable smtp server so that you could have an app that sent email without ever asking your users to put in their SMTP server info... it was USELESS because of SPF filtering. The blacklisting of whole IP ranges means that no app could use it on a home computer because all those IPs are banned.

we definitely need a better solution to fighting spam.