Count me as one of the surprised ones. Remember: just five days ago, it wasn’t even 50% funded.
My biggest worry with App.net (apart from its very stark name) is that it lacks the social component of “social network”. It’s not just the $50 barrier to entry, because other sites had similar new user restrictions. Facebook was initially only available to the students of Harvard, followed by slow rollouts to various universities, high schools, and communities. But it was solving a problem: its focus on using real names improved its ability to connect communities (“networks”, in Facebook parlance). Google+, on the other hand, is just Facebook by another name. Its invite-only beginnings didn’t help it grow, but I doubt it hindered growth.
App.net is very close to Twitter in functionality, so I can’t see the average person paying $50 to join. It therefore becomes a special club, like Twitter in 2006 and 2007 (remember when you could view a live stream of public tweets?).
App.net’s special club has two advantages. The first advantage is that it gets rid of trolls and spammers. This has worked well for Metafilter, which charges $5 for a new user account. The second is that it means users won’t have to be put at the mercy of advertisers and VCs who are looking for a return on their investment. App.net will be full of Twitter refugees, as it isn’t looking so rosy any more for us geek-types:
Between shutting down API access to Instagram users, and delivering a “consistent experience” (amongst other nudges in the direction of a vertical Twitter ecosystem), it’s not looking good for those who love the Twitter experience of yore.