>>>these eavesdropping measures will be used against who exactly?
>
>The reality is that email is fearfully difficult to keep private because of uncontrolled transmission via intermediate servers. Even phone traffic is likely to be VOIP somewhere along the way these days, meaning it can be snooped without a warrant. Experts also say that international email almost always goes via a US IP address in Virginia where it can be invisibly snooped. But people don't seem to care- consider that Google freely admits to perusing email to target advertising better, but millions of people use gmail regardless.

That is incorrect. The reality is that email can easily be encrypted and secured against most all intrusion attempts except perhaps state agencies with massive resources. Even then, current strong encryption techniques I think are still unbroken (PGP, AES, etc.)

3rd party, online mail servers (gmail, hotmail), etc. are obviously not under your control and thus only require the owners to provide access to inquiring agencies.

Your phrasing is misleading. Google do not "peruse" emails. Automated software scans emails for keywords and phrases and tries to add adverts that might be relevant. Humans are not perusing them. But that is not the problem with 3rd party mail providers anyway.