So why do you, and others, seem so upset with a proposal that *is*, in at least some regards, more secure and more useful (to large ISPs)?

SPF doesn't meet their (Yahoo's) needs, for several reasons. It *isn't* useless, but it's nowhere near as useful (to Yahoo and other large ISPs) as the crypto solution. And it does diddly for the legal side of the matter.

I was (and am) fed up with this extraordinarily ill-founded idea that Yahoo apparently 'should have' adopted SPF rather than craft a solution that fits their needs (perhaps best encapsulated in the observation that the phrase 'most natural' has little to do with any tangible problem). The _fact_ is that SPF _didn't_ fit Yahoo's needs, and rather than address those deficiencies in SPF, all I've seen from you (and others) are arm-waving explanations that SPF is, apparently, good enough.

Don't get me wrong: it may well be good enough for you. But it obviously isn't quite good enough for Yahoo, hence their own proposal.

And one of the merits of their own proposal is that it will be useful *to Yahoo* even if no-one else adopts it...

The RFC's and standards bodies are littered with standards that are fully-formed but simply don't address a real need, or don't address a need well enough. Just take a look at ANSI standard tape formats! SPF looks adequate for what it does, but for essentially the same administrative overhead, 'YASAF' does more, including the issue of providing legally useful proof of origination.