Because every decent project related to OpenStack has to go through at least one rename. ;-)
Actually there are practical reasons behind this rename. First, it turns out a lot of people think you're joking if you start talking about QuintupleO (and to be fair, the name started out as a very tongue-in-cheek thing). More importantly, OpenStack Virtual Baremetal has applications outside of just TripleO, which is a fact that tends to get lost in the Stack-ception of the old name.
To that end, I've created https://github.com/cybertron/openstack-virtual-baremetal as a repository for the docs, templates, patches, and such that are required to set up an OpenStack Virtual Baremetal environment. I should note that Steve Baker deserves a lot of the credit for what's in that repo as he did a lot of the work around automating/simplifying some aspects of the setup. Which I then shamelessly ripped off and shoved in my renamed repo.
For the moment I'll probably keep tagging posts with QuintupleO, but you will also note the new OVB tag on this post which is what I will be using in the future for anything related to this.
That's about all I have for now, but I need to make another OVB post soon with updates on the current status. Apparently it's been six months (!) since my last update and a lot has changed since then.