Could be a pretty cool UI solution to have a chat client that uses PGP encrypted e-mail in the background, but Gmail SMTP has a send limit of 100 e-mails per day. You would run into that rather quickly with a chat UI.

I guess the chat client could do all the e-mail sending from some of their maintainer e-mail servers and not from under the chat participant e-mail. Then we would start losing comaptibility with other e-mail clients though. Although not completely, as we could set Reply-To headers and when another e-mail client replies to [email protected], we could just forward it to the correct e-mail.

An interesting concept indeed.