Sender authentication hops off the standards track
After a falling out last fall, email authentication movements from
Microsoft Corp and the Sender Policy Framework community are, for now,
going their separate ways within the Internet Engineering Task Force's
standards process...
[snip]
...However, three quarters of a million users to date means that
practically speaking it has already gone beyond the experimental phase,
and that it will be a fight in the marketplace for recognition as the
de facto standard. And it appears, so far, that SPF is winning.
http://www.cbronline.com/article_news.asp?guid=44D2955C-3C04-4BA1-AC45-
AF8277B8B455