Sender ID conflicts with many of the US ECPA provisions. There doesn't
seem to be much thought put into to see if it passes the legal muster.
SenderID is not a reliable concept and it promotes the obstruction of mail
delivery and it promotes local policies to be applied at the wrong
part of the mail operation. It promote post acceptance Local Policies
rejections ideas for any discriminatory whims beyond spam. Where do you
think "local policies" evolved from anyway? Not because it was a "neat"
idea. It all began with te 1986 US ECPA provisions to help address mail
delivery obstruction, mail tampering and privacy issues. I'm not just
blurting this out. It has many legal issues.
Sorry the other poster didn't respect your insights just because While I'm
not sure about your anger towards Microsoft (I do share my disapproval,
though, since Outlook turned innocent email data into executable content
without anybody's permission and started the virus revolution that has help
drive the spam deluge, along with other helpful things like hiding "known
file extensions" so once scary filenames look innocuous: i.e. hello.html.exe
would be displayed as hello.html since the '.exe' was a known extension!).
Unfortunately, the ECPA has no doubt been gutted by the Patriot Act I & II
provisions, but the idea is right. At this point, these systems are saying
that they will accept/reject email sent by others to people, but neither the
sender nor the recipient has any say. That is a violation of ECPA, and of
course many spam filters at ISPs have violated the law for some time.