It would be mediocre if it was simply an "open api" twitter/facebook but, given the chatter on the Alpha site and the look of the API on git (https://github.com/appdotnet/api-spec), I think there is something bigger going on here.
Its a cool api, and I mean no disrespect to anybody involved like the guy said above, I just believe the business as a whole is a kneejerk reaction to a couple of well connected people and sites getting the rug pulled out from under them. It would be cool if they could get enough people to use it, but the API is only useful if there is useful data to pull from it.
It's not exactly a knee-jerk reaction to an isolated incident though. Twitter has been moving in the media company direction for a while now, and with the latest communications you can almost see the "fuck you developers" oozing out from between every line of shmarmy corporate-speak.
Any developer would be a fool now to build a product whose core relies on Twitter's API. And yet the core functionality of Twitter is an incredibly useful base to build on.
With App.net you don't have the volume of Twitter, but on the other hand you will presumably have a much higher signal to noise ratio. It won't be inundated with marketing spam, bot follows, and banal teen banter. And in any case, Twitter was small once too, and people found a use for it. I think a critical mass of 10,000 is definitely enough to enable some interesting apps.
