But with the security/encryption/signing for email... yeah, if it was just an "on" switch somewhere, I'd be all for it. Unfortunately, setting up SPF for something like exim isn't very straightforward at all. It's flipping LOTS of "on" switches in lots of different places, generating and copying keys around, setting permissions on all the files properly, testing etc. It turns into a legitimate project fairly quickly, and it's hard to prove that this is a better method than just really well-trained spam filters. So, basically, it ends up being by Google fiat that I had to do that project.