To what extent do free email services such as gmail & yahoo look at the contents of your emails?

and for what purposes?
To what extent do free email services such as gmail %26amp; yahoo look at the contents of your emails?
They don't look at the contents of your mail in the way you are thinking if at all, If they do monitor your activities they most likely have a system in place that looks for key words in emails. Gmail and Yahoo will not report you to anyone however, they could be required to turn over information to the authorities. You should be more concerned about your emails being intercepted by other users.