Facebook on the other hand, embraces the open web, and sinks it's hooks in via extremely elegant and lightweight hooks like Login with Facebook and FBJS that have impeccable usability and deliver measurable value to site owners. They are not fighting against current trends, rather they are defining and riding them.
Facebook will not be in trouble until their business model starts to collide with user interests. Privacy concerns are a potential problem for them, but don't fool yourselves that even a sizable minority of users care about that yet.