It’s important to be clear that Instagram is not going away. We’ll be working with Facebook to evolve Instagram and build the network. We’ll continue to add new features to the product and find new ways to create a better mobile photos experience. The Instagram app will still be the same one you know and love. You’ll still have all the same people you follow and that follow you.You’ll still be able to share to other social networks.
An encouraging sentiment from Instagram, but I'm skeptical. Facebook doesn't have a great track record of buying things and making them better. "Build the network" sounds like a euphemism for forcing users to log in via Facebook, rather than Instagram's own login system. Moreover, Instagram became a hit because of it's great iOS app, while Facebook has a terrible iOS app. Neither is particularly promising.
In short, it's hard to imagine Facebook making Instagram better, and easy to imagine Facebook making Instagram worse.