I have seen a couple of threads on this already... but by what some other people described I am not sure I have the same problem. I can't seem to be able to post, like, or reply to comments on videos and news stories. In the box that you're supposed to write a comment in, it simply says "Sign In" - even though I am signed in. Other people's comments aren't marked with dates either.
Anyways, just wondering if this is a problem on my end or if I did something to get my permissions taken away (can't think of anything I would have done to have that happen, though).