I'd been reading here about Hushmail and having used it before I was wondering if Hushmail's mail is any more secure than regular email when sent outside it's network? The account itself has good security features but once you send the message out on the internet it's open to tampering like any other email, unless it's PGP signed or something like that but even then most of your webmail providers don't support PGP and security certificates.
What am I missing?
Even though your question is old there is one thing yet to be said.
Hushmail always tries to send all mails via TLS/SSL, i e establish an encrypted channel between its mailserver and the receiving server. If the receiving server accepts, then that message will be transfered encrypted. However when saved on the receiving server the mail itself will be saved unencrypted (unless the server is Countermail which encrypts incoming mails). Hence if the mail is sent by using TLS/SSL then it cannot be read or modified in transit.
Today I would say a lot of mailservers accept TLS-transfers and use it themselves when sending.
If you want to check, you can try by sending a mail from a Hushmail-account to that email host you want to check. When you received the email, check its headers and look for TLS-markers.