FWIW, I looked at the survey before I saw John's note and decided on my own not
to take it. AFAICT it's intended to assess what SPF policy, if any, has been
implemented by the responder on their own host(s).
If you want to ask questions of an audience of implementors, I suggest that you
ask them what kind of support for SPF do they provide in their products and
perhaps what they know (or don't know) about actual customer usage of those
I reached the same conclusion. I have five different mail receivers I
use on a daily basis. Each handles SPF quite differently, ranging from
no support to a textbook implementation to a datapoint in a spam scoring
engine. Two use commercial products I either designed or maintain. I
would guess Ned and anyone who implements mail handling technology for a
living has a similar range.