Yes, but they COULD. If for some reason they decide that something's wrong with their host, they could just go offline, export the data onto a new host somewher

Yes, but they COULD. If for some reason they decide that something's wrong with their host, they could just go offline, export the data onto a new host somewhere, move some DNS targets and set up some redirects, and bam, new server. The point is that some one social media company doesn't have a lock on the site.