I also don't allow any app requiring those details (unless they are needed obviously, like VoIP), but I think what most companies want is the unique serial numb

I also don't allow any app requiring those details (unless they are needed obviously, like VoIP), but I think what most companies want is the unique serial number, so they can keep a track of how many unique devices are used by them. But since Android does not gives permission at more granular level, I simply don't install any such app, or don't upgrade one which ask for it. As for Facebook, I am using Tinfoil for Facebook app (It is a website wrapper, essentially). It was faster than whatever app Facebook managed to write.