gzt:ubergeeknz: People need to get in the mindset that the Internet is a public place, and anything you do in a public place could be monitored by other people.
This is kind of true and kind of not. There are long established legal rights to privacy. Interception of private communication is illegal in many of the examples you give. It is not unreasonable to expect an ISP to comply with the law - not that there is any reason to think otherwise in this thread.
I'm not saying whether it is legal - I am saying it can (and does) happen.
And Government agencies typically have the ability to legally monitor peoples activity, or compel others with the capability of such to do so.