>A basic friends-only system isn't that expensive to run. A low-budget operation like Craigslist could do it with a modest staff. A low fee or infrequent ads co

>A basic friends-only system isn't that expensive to run. A low-budget operation like Craigslist could do it with a modest staff. A low fee or infrequent ads could bring in enough revenue to keep it running. The technical aspects of such a service are trivial. People try to build new social media sites every day. The problem is building up a network effect. Getting to the scale of Facebook may not ever be possible again for a small startup because the friction for switching services is so great. Until there is some massive technological leap like the internet again, there's really nothing compelling enough for the average person to bother.