I'd imagine an issue is that there's just no place to go for it. If a big existing community introduced annotations, I'd bet it could catch on. Imagine clicking

I'd imagine an issue is that there's just no place to go for it. If a big existing community introduced annotations, I'd bet it could catch on. Imagine clicking through an article from facebook and you automatically get annotations. Hell, on mobile you already have these apps using built in browsers so you don't leave the app. Something like that, where annotations are discoverable, could definitely gain traction. Then there'd be no escaping facebook (or twitter or reddit or HN) even on other sites.