I don't think that's what "too big to fail" means. It doesn't mean that you are so big that failing is impossible, it's that you are so big that if you fail you

I don't think that's what "too big to fail" means. It doesn't mean that you are so big that failing is impossible, it's that you are so big that if you fail you'll take the whole industry with you, thus it's politically untenable to allow you to fail. (Mind you I don't subscribe to the view that these things should be bailed out, I'm just explaining the phrase.) I don't think Facebook fits in that category.