more validation methods, was spam down?

On Wed 30/Jan/2013 16:40:06 +0100 Chris Lewis wrote:
> 
> Validation is so irrelevant that the spammers impersonate sites when
> it's clearly unnecessary.  They use their facebook impersonation
> templates to send out pill spam for crissakes.  If validation was making
> a difference, the ROI would suffer.  I can only guess it isn't.

That seems to be true, sadly.

Looking at myself, the reason why I don't use authentication results
is because so few messages bear any.  If they covered a significant
percentage of messages (and spam), I'd use the data in those A-R
header fields to send complaints, implementing RFC 6650, according to
the discussions we already had.

A way to enlarge the covered base is to add more authentication
methods.  For example, "dnswl" would be quite similar to "vbr",
"iprev" is already defined, "rdap" is a promising new feature.  By
adding those, I'd expect it will become fairly difficult to find
messages with no authentication at all.  Correct?