Eleventh Circuit Decision Largely Eliminates 4th Amendment Protection in E-Mail
volokh.com
volokh.com
Looking at it from a different angle, perhaps (note a hint of devil's advocate here) we should be glad that modern cryptographic systems (enabled by the very tech that seemed to threaten privacy) offer the potential to make old-fashioned laws superfluous?
I sign all of my outgoing emails using Thawte (now Verisign) certificates. The problem with encryption is finding the other person's keys. I have yet to receive a signed email from someone else, so I cannot send encrypted messages.
It seems to be a problem primarily with critical mass and secondarily from implementation. Not enough people use signed/encrypted email to spur others to using it. Additionally, certs cost something. Even free certs cost effort in understanding the need for them and figuring out how to generate/download/install them. Then there is the whole problem with "trusted" certs...
Implementation wise, things are only a little better. Once the certs are installed, (desktop) mail clients handle the signing/encrypting pretty well. But I can't sign messages from a webmail client or from my phone.
You need your ISP to store the emails encrypted even if they were received in the clear.