InfoWorld: Spammers using sender authentication too, study says.
But Wong, who co-authored both the SPF and Sender ID standards, said
that stopping spam was never the intention of SPF or Sender ID. The
technology is merely a way to stop one loophole spammers use: source
address spoofing. Evidence that spammers are publishing SPF records is
a good sign, Meng said. [Tomalak's Realm]