Google is one of those providers:

http://searchengineland.com/google-fired-two-employees-for-b...

http://www.wired.com/threatlevel/2010/01/operation-aurora/

http://readwrite.com/2010/09/27/googles_second_transparency_...

Google read your email and use it to throw targeted ads at you.

There is a fine line between profiling, tracking and analysing communications and utilising that data for something nefarious. The only deciding factor on how far it goes is cash.