I do PGP sign my emails but not the mails that my little web app sends out. I should try that and see how users do react.
How's the state at the receiving side? I mean what percentage of users would be displayed a message about the PGP signature being valid despite them neither using nor knowing about PGP?
I don't think there are many clients which support PGP out-of-the-box. The state of S/MIME is better though; I believe many desktop email clients already support it by default.
Still, more work needs to be done. It's a bit of a catch-22: no one is signing their emails because client support isn't that good, and client support isn't improving because no one is signing emails.
How's the state at the receiving side? I mean what percentage of users would be displayed a message about the PGP signature being valid despite them neither using nor knowing about PGP?