Honest question: what stops you from simply browsing a twitter list of those twelve people?
Or, more pragmatically: what incentive do I, a person who doesn't really care about 'openness' and uses Twitter for a billion other reasons anyway, have to pay $50 and subscribe to app.net instead of just following the twitter list of those twelve people?
Twitter is fine now, but, over the next few years, will become increasingly polluted, and brought down by the mandates of Twitter Inc. having to be a multi-billion dollar company, and make money off eyeballs. Twitter is _fine_ right now - I can chose my client, I can follow a clean feed - (all of the above are in my feed). There are NO problems whatsoever with twitter, for me, right now. In the next few years, that will likely change. Clients will become restricted, the feed will become polluted, and my eyeballs will be resold.
I like to get ahead of the curve.
I use Path, not Facebook. I don't watch commercial TV w/commercials. And I support app.net. Their business model is pretty straightforward - "The user is the customer, not the advertiser."
I like being the customer. That's why I'm paying $50. It's also why I'll migrate off Path to the first company that comes up with a business model that also foregoes selling my information and attention (While, like twitter, it's pretty close to perfect for me right now, I'm sure Path will go downhill - unless they find some ueber clever low-overhead approach akin to what Craigslist has been able to do.)
The incentives are A) to hedge against future developments of Twitter throwing you under the bus for $0.50 and B) joining a social network of people who explicitly value that network who you believe will have a generally higher signal to noise ration than the unwashed masses.
Today you can follow those 12 people, but if this takes off then it promises a return to the nostalgic '06 and '07 of Twitter when the community was small and everyone there was "interesting". The cognoscenti of tech may well abandon Twitter in favor of this un-walled, membership-only garden.
Now who really should care about this? Certainly not most people. It won't compete with Twitter, but it won't have to because it will have a fraction of the infrastructure costs, and it will avoid the eternal september that plagues every popular free service. This will be a niche product, but if successful it will potentially be highly valuable to that niche, and also it will be quite novel as a paid product of this type has never taken off as far as I know. If you really buy into the hype, you might even think that the success of app.net could signal the high water mark of free services as it becomes apparent just how much better a service can be created when it's paid for directly by users.
I'm not saying I believe any of this, but I do see the potential.
Point of information - the precursor example of a social networking product supported by users might be http://en.wikipedia.org/wiki/The_WELL , which had a good 20 year run.
To be honest, I used Twitter initially because it was interesting to read and be in dialogue with the larger tech community in a way that I might not on, say, my Facebook (very technical discussions, etcetc). I could of course browse a Twitter list of twelve people, but the way I am willing to participate in Twitter changed the moment it became more than a tech ghetto. In fact, Twitter became essentially useless to me on that day. I could really think of worse things happening than another such niche social network emerging... Consolidation, especially of data, is incredibly overrated.
Or, more pragmatically: what incentive do I, a person who doesn't really care about 'openness' and uses Twitter for a billion other reasons anyway, have to pay $50 and subscribe to app.net instead of just following the twitter list of those twelve people?