The idea of a platform dedicated to sharing photos and videos thriving in a world of 28k modems just caused my mind to boggle...
Well, if it's big among college kids at first, maybe an earlier use of T1 lines at universities would make it workable. That would mean colleges would have a LOT of use of their servers for Facebook, which probably means fee hikes and faster installation of T1 into dorms.
It probably makes the leap to people's home computers faster, since cable modems became a thing in the mid-90s, but it starts off with techies and people who can spring for cable internet.