There are some good surveys about spam, viruses etc -
but I didn't find something interesting about encrypted eMails.
Due to the absence of a working key-distribution system
encrypted mail is mainly a nice theory. You will probably
get messages from people claiming that they are "encrypting
e-mails all the time" but they do not represent the bulk of the
Actually, there is a de-facto system for secured messaging
that has considerable advantages over S/MIME and that is to
use e-mail notifications containing https links to web-sites
where the user can (after authentication) access messages which
does not have to be encrypted as the communication between
the web-site and the user is protected by SSL. This scheme
also allows a user signing off that he or she really has seen
(downloaded) a message. This is the scheme e-governments
will most likely use for C2G messaging.
Another problem with message encryption on a wider scale
is that if you lose the encryption key you probably lose the
information as well.