It's generating a lot of buzz. I've been doing some R&D w/ it for the last 6 weeks.. It's quite impressive.
I used to use containers w/ Solaris back in '05 to support oracle enterprise stacks (rdbms 10g, oracle AS 10g, OID/SSO) inside solaris 'zones'. It was great when set up properly to support snapshots and what not.
Docker does similar, but can run any linux distro that the host kernel supports... genius! No more installing RPM/deb packages and worrrying about dependencies on my hosts!