I don't have a Facebook account (and I refuse to get one), so in the unlikely event that people like me are the sole target group of your application/website, yes - requiring FB connect will kill your startup =)
But like I said, it's unlikely.
But like I said, it's unlikely.
For one, most people in our target age demographic (say 16 - 34) do have FB accounts. The other assumption is that if you don't have a FB account, you're less likely to want to talk with strangers over videochat.