That's kind of a low-resolution summary of what we were saying -- you can annotate code on omniref, and we'll carry those annotations forward/backward in time, until the code changes.
It's part of our way of dealing with the problem that happens on StackOverflow all the time, where the top-rated answer is completely out-of-date.
Wait, don't comments do that?
(edit: oh, they mean like forum comments, not like source-code comments?)