the only question I have: How are the developers protected from facebook launching similar products when their product proves that it makes money or draws a lot of traffic?
Even if you don't use facebook's platform, they can still launch similar products. The bigger threat is facebook discontinuing the platform or restricting what you can do, though I doubt they'll do either.
Vaild point, but no need to shout! Theres always a risk when using a platform. There are some ideas that you can do which facebook itself are unlikely to eg mosoto
Good point too! To me this feels like signing up for a franchise instead of starting your own business, you have control, but not full control. For some purposes or ideas it's a great.
Edit: Fixed