The idea that anyone would sell any project for 1bn is kinda nonsense, if a project looks worth buying for 1bn to someone, it may look to be worth keeping to the people who made it or are in control of it.
There are a lot of projects I would sell for $1m, but it is little enough that I would carefully consider for anything I've invested serious time into
though id have the utmost respect for someone who could hold onto the possibility to threaten the facebook/instagram/snapchat moat, realistically i don't think anyone in here could stick to the ideals so strongly.
it's not even a valuable thought exercise. if this thing were to gain any traction at all it's assuredly gonna get acquired. you gotta be tech-buddha to resist that.
The domain would dominate sign-up flows.