If anyone is wondering how to make your email a bit safer from the variety of prying eyes that have turned up recently, I would like to recommend this [basic write-up at Ars Technica][ars]. The overview is good, but the article gets a bit lost when it comes to narrating the procedures involved.
Unfortunately, since encryption really requires an investment by both the transmitter and the receiver, I don’t see it gaining much traction until it becomes dead simple and baked into things like mail applications. Those who use services that are not free may get this sooner than those who rely upon advertising-supported services. After all, if Google (or Hotmail or whomever) can’t data mine you, then they can’t sell you. (And, hey, if you think I’m being snooty here, I’m not. I also rely on GMail for some chunk of my email infrastructure — if anyone can recommend a reasonably-priced IMAP mail provider, I would gladly try it out.)