Most people just don't realize that email is sent in the open and can be intercepted and ready by dozens of people between you and the person you're writing to, which might make you nervous.
I sometimes use gpg to sign my mail at home. Here's the (potentially out-of-date) info on my keys, for reference. Just check the keyserver at pgp.mit.edu, it'll always be correct. I think.
pub 1024D/1F87615A 2002-03-17 Key fingerprint = 829A 0EBB 9702 5A76 9ED3 9211 D311 4D46 1F87 615A uid Eric H. Weigle (Personal) <email@example.com> uid Eric H. Weigle (Home) <firstname.lastname@example.org> sub 2048g/95394528 2002-03-17
For historical reference, here is my previous work/school key information. I no longer use this key, but see no reason to revoke it.
pub 1024D/59EA9C4F 2002-05-28 Key fingerprint = 112E F8CA 12A9 771E DB10 6514 D4B0 D758 59EA 9C4F uid Eric Weigle (CSAG key) <email@example.com> uid Eric Weigle (Work key) <firstname.lastname@example.org> uid Eric Weigle (School key) <email@example.com> sub 1024g/512A8C19 2002-05-28
You can also download my public key here, if you trust Google sites.