one of the big differences i can think of off the top of my head at 3am is that FB still isn't really about discovering new friends. You meet people in real life, then you friend them on Facebook. Not vice versa.
As far as I can tell, something that Color is expanding into is creating this "temporary" social network where you share photos with anybody within a certain location. It isn't as much about sharing photos with friends that you already have, as it is about discovering new people and the photos they're taking around you.
Based on widespread privacy concerns that Facebook has had to deal with, I'd say it's unlikely that this app involves social discovery. It's probably another friend, photo-sharing app, with the permissions of sharing mirroring what happens on the Facebook webapp.