Yes, I know what it is, and I also know the Gnu version, GPG, and about the OpenPGP standard.
Do I use it for email? No. Why, if I was whining so loudly about my beloved Lavabit shutting down?
Because 1- I just don't go emailing around sensitive information that would require it. I'm not that important and neither are my email messages to friends and family. My primary concern was to prevent "casual hacking" which might reveal passwords or other information I had stored in email (not smart, I know, and I started using POP3 instead of IMAP after someone apparently brute-forced my password to start sending out spam. *sigh* Different story.)
2- I would have to teach my brothers, mother, grandmother, cousins and aunts/uncles and friends all about how to use it and why they can't read emails from me unless they did. No thanks.
In my post about Lavabit shutting down, I described my very simple reason for using an email service that was encrypted, and it was about simple prevention of "casual hacking" which might reveal passwords or other information I had stored in email (not smart, I know, and I started using POP3 instead of IMAP and erasing messages from the server after someone apparently brute-forced my password to start sending out spam. *sigh* Different story.)
Anyways, I do use GPG to encrypt my password vault, does that count?