I've seen signup success rates between 30-97% with conventional login systems. There are two things that appeal to me about Facebook: (i) people take their Fa

I've seen signup success rates between 30-97% with conventional login systems. There are two things that appeal to me about Facebook: (i) people take their Facebook identities seriously, so they're less likely to be griefers, and (ii) the like mechanism to push back updates about items that have changed