But now that gmail has ssl access, this is no longer true, right?
"Reasonable expectation of privacy" doesn't have an implicit "only as against the government." If you're knowingly exposing the contents to Google and Microsoft to scan, you can't claim to have a "reasonable expectation of privacy" in the contents.
I've stopped putting my public key on emails I send, because almost no one ever encrypted email to me, unless they were specifically sending something perceived to be sensitive.
The ad-bots at Google aren't known to be very gossipy.
(I don't mean this to be snide. I think this is an instance of a very interesting phenomenon, where we reason about our society as if it were a village.)