I guess that depends on what you mean by privacy.
I tend to define privacy in terms of an intersection of users' expectations and preferences -- data should be used how users expect it to be used, and those expectations should match their preferences.
For example, a particularly voyeuristic user might truly prefer -- independent of any transactional considerations -- for marketers to know a bunch of intimate information about them. In that admittedly entirely fictional case, the modern web isn't a privacy violation.
My point is that it's possible to use data for a particular purpose without violating users' privacy expectations and preferences. There are both legal and technical mechanisms that enable these sort of use cases.
I think it's fair to say that most people expect and are perfectly OK with google using their email to filter spam and improve search. Therefore, I don't consider those use cases to be privacy violations.
Also, although search and filtering are two huge features GMail, even a GMail without those features would be quite superior to Squirrelmail/Roundcube/Yahoo! accounts with tiny data limits (which really were the alternatives when GMail launched).