OpenPGP usage

Mail
Mail User Agent integrate OpenPGP (Enigmail, mutt, mailcrypt...)
Jabber client using OpenPGP

Software distribution
Free Software includes signed distribution files

Collaborative work
Debian keyring (~900) (Software release & daily work)
ReseauCitoyen Keyring (~30) (VPN between nodes)

Software / Binaries signing
GNU/Linux ELF binaries signing http://jukie.net/~bart/elfpgp/