How about reason 0: You depend on a platform that can shut you down in an instant without any justification and without possibilities to reactivate your app?
this argument comes up over and over when talking about facebook APIs etc, but this is an inherent risk in all kinds of online and offline applications: from the electric power company to the ISPs, to browser vendors, to facebook, there are all kinds of dependencies you have to rely on. True, facebook is more likely to have conflicts of interest with your web app. But the main issue is that facebook doesn't yet have a financial interest to maintain a healthy app ecosystem.
> If browser vendors simpy start disabling browsers, we have much bigger problems.
There is enough competition in the browser market that selectively disabling certain sites will lead to a big loss in market share, and would be an exceptionally stupid move.
Crushing apps is not a big problem (Zynga still earns more than facebook itself). The problem is we cannot sign an SLA, or have any other contractual relationship with facebook, even though they take a 30% cut or ouf virtual currency sales.
Still, for a company that is essentially a parasite on facebook, the money they earn is staggering. They could even earn a lot more if they used advertising on their games (they stopped using ads in 2010).
