I've been banging my head against the wall for the past few days wondering why GPGMail was ignoring my private key (PGP/OpenGPG key for encryption and signing e-mails/stuff), and I finally remembered I'd set it to expire in a years time, which it has done and so GPGMail was merely ignoring it because I could no longer use it.
I've now got a new key for anyone who cares, you should be able to pull it off the standard PGP.com key server anyway, but I prefer having it on here as a bit of extra proof of who I am.