PowWeb adds SPF to mail servers

I was pretty happy today to see that my webhost has added SPF to their spam fighting techniques. This needs to see more widespread adoption.
Right now if someone sends out 10 million spams from my domain to 5 million servers on the internet, roughly 80% of the spam will be to a bad address. An NDR would be generated and sent to me. Its a rather effective denial of service attack, assuming you can insulate your self from identification as the attacker. If those servers implemented SPF they would see that the message isn’t from a valid sender for my domain, and hopefully drop it. Instead many senders send an NDR without enough of the original message, so it doesn’t get caught by my spam filters. Not sure if I’ve explained that well or not, its pretty late. It is too easy to get your mail servers DoSed indirectly by some spammer.