I'd like to encourage the world to use encryption—after all, you'd never send your private paper correspondence on postcards, which is essentially the practice in e-mail where anyone can read your message in transit—but my desire will probably come to nothing. Though encryption software is freely available, no one uses it.
I've had to post a new public key. My old keys are protected by the patented IDEA cipher, which is not supported in the reigning free personal encryption software, GnuPG. If you have to send me encrypted material, use the newest signature.