The question about the gummint reading emails is silly. Could they? Yes. Are they? Gawd, no! At least, not everyone's.

Think on it for a moment. How many millions of emails go out in just California alone every day? In the US? In North America? Worldwide?

To check for keywords takes a fraction of a second. Multiply it by the keywords being searched for and the numbers of emails sent. Then toss out those messages in which the context precludes gummint interest, like, "I thought "Shrek 2" was a real bomb." Include misspellings: "Bumb" "gon". Then include deliberate dialectization or slang: "Waal, I done got myself a l'il ol' pissle ta use ta blow 'way tin cans."

Now include the emails that aren't sent over the Internet, but remain on internal servers, often behind firewalls.

We haven't even talked about coded messages: "Amos, the ship will arrive at 1700" could mean that the bomb will go off at 1900 or it could be just what it purports to mean.

And what of those (such as myself) who have several webmail and email accounts?

Pinpointed to an individual or output from a particular site, yes. Blanket filters of the Web and the Internet? Come on, it ain't worth it.