I use it primarily for PGP. I've been thinking about trying out Linux from Scratch with it, but haven't had the time.
I made a decision to start using the Chromebook to dogfood this particular vision of computers: I'm not happy that it involves Google, but they're the only one with an implementation that's this far along, unfortunately.
I've been meaning to write on this whole thing, haven't had the time...
0 - http://words.steveklabnik.com/returning-to-free-software-a-g...