The MailPile page (https://www.mailpile.is/) mentions GMVault (http://gmvault.org/) as their method for backing up Gmail. I haven't heard of GMVault (or MailPile) until just now. Both look promising. I'm glad there is a push in this direction.
I've been using GMVault for the past month and I have really enjoyed it. I wrote a cron job to periodically pull down my latest emails and back them up (encrypted).
Does GMVault store your mail on your machine in a text-readable (I include XML in this) format? Because if it's a binary blob, it's not as useful as it could be.
All emails are stored individually as EML files which is just text. It can also export all your emails into the standard maildir or mbox format so you can easily import them elsewhere.
