We've recently added the ability to automatically encrypt all your incoming messages to your PGP key before saving them to disk.
This way you can ensure that your messages saved on the server are encrypted at all times.
Note however that many email programs won't be able to search the contents of encrypted messages very easily. Also remember that if you lose the PGP private key needed to decrypt the messages, you will not be able to recover your messages, and neither will we!
Automatic PGP encryption applies only to incoming messages, and will not currently encrypt the contents of your Drafts and Sent mail folders. It also does not apply to messages larger than 1MB in size.
If you'd like us to enable automatic PGP encryption of incoming messages for your account, just contact us with the PGP public key you'd like the messages encrypted with, and we'll get this set up for you.
If you'd like to enable automatic PGP encryption of incoming messages only for specific addresses at your subdomain or domain (or for all except certain addresses), we can set that up too.