If your business model is reliant on annoying the users of a proprietary 3rd party platform, you shouldn't be surprised when the rug gets yanked out from underneath you.
The point was that if Facebook are providing the APIs and encouraging developers to use them then it's a crappy thing to yank the rug away.
I don't think that it's a great idea to build a business model that relies on Facebook - but at some stages of developing an app it is very useful to use Facebook facilities to implement a social graph and notifications, so that you don't have to.
> "I don't think that it's a great idea to build a business model that relies on Facebook"
Correction: it's a bad idea to build a business model that relies on screwing Facebook, on Facebook's platform.
One of Facebook's priorities is keeping its users engaged and happy - invite-heavy, spammy apps run directly contrary to that goal (in a very egregious, very serious way). It is no surprise that Facebook slammed that door shut.
This is generalizable to: if you are reliant on a third party platform and your interests are aligned against the interests of the platform, you will fail.
> One of Facebook's priorities is keeping its users engaged and happy
Engaged, yes. Happy, bullshit. Facebook ignores its users and abuses them far more regularly than most other companies. Anecdotally, everyone I know hates facebook and wants an alternative that has active users. By numbers, Facebook was the last in brand satisfaction for its market in 2011[1], although ACSI appears to have died since then. I strongly suspect the reason facebook restricted notifications was because they weren't making enough money to offset e.g. disabling of notifications.
They're willing (and smart) to leverage independent efforts where they assist this. But... only so long as they do.
Look at it from this perspective: If a functionality becomes important, would they not be "derelict" in their duty not to attempt to bring it under their control? In-house, acquisition, whatever.
If you choose to help them out, they're not going to say no. But you should keep the balance of power in such a relationship in mind.
I don't think that it's a great idea to build a business model that relies on Facebook - but at some stages of developing an app it is very useful to use Facebook facilities to implement a social graph and notifications, so that you don't have to.