Here's the API spec:
https://github.com/appdotnet/api-spec
If you're using it to talk directly to users, it'll be tough to beat free social networks, because that's where the traction is.
If you're using it as the back-end of an app, it'll be tough to beat something like Celery (https://github.com/celery/celery), or a hand-rolled MySQL solution. Seriously, if you look at the API tree, anyone who knows anything about databases can probably hack something with similar functionality together in a day (minus UI).
The one point that app.net might have in its favor is scalability -- if it "just works" when you have a gazillion users.
app.net would be a lot more comprehensible if the author listed a few sample application ideas and told what pain points app.net was supposed to solve.
There's no way I'm donating, when he can't even clearly express the problem he's trying to solve, let alone how his solution is supposed to be better than Twitter.
Pros: Developers work to please the user (you), not the advertisers. No ads.
Cons: Not free. Harder to get traction (because it's not free)
Why? Because their view is that current projects don't focus to please users.
Watch the video.
That's my thinking anyways.
It's not a bad trait to have, actually.
But he didn't convince me about what it exactly does? That's why I just asked.
Sometimes this discussion might help him to create a good web copy for http://app.net and get more paying users for his product. (I think there may have lot of people like me)