Actually, I think I'm referring to ThirdVoice, which was shut down due to lack of success, and websites didn't like it because it "externalized discussions" according to the wikipedia.

https://en.wikipedia.org/wiki/Third_Voice

Also there are many other web annotation systems described here: https://en.wikipedia.org/wiki/Web_annotation and the see-also section shows several failures.

As I said, I personally don't think this is a good idea, I can't see the point, but best of luck in any case, I guess at least some others are finding it useful.