The idea is good, but the implementation can be improved. Instead of making the background of the entire post blue-ish, you could use a more subtle method, like adding the text
(Original author) beneath the author's name, or adding a subtle colored border around the author's avatar.
I agree, I like the idea (although I have no idea yet what I'd do with that info), the way it's presented is too much.
I think even giving the post header a different colour would be too much. I think adding something under the avatar and username is a good idea.