Ask HN: is web highlighting service topical today?

Idea of one service blowing my mind last year: to create a service, which allows to highlight main ideas in web articles and shadow noise information. Imagine two markers, green and gray, which you use to mark articles everywhere on the web. And your markings visible to all users of service (unregistered even). Social highlighting, meta-wiki over Internet. My fears: - there were many highlighting services before (shiftspace, webnotes.net) and only Diigo is alive now. BUT: all of them is person centered, when goal of my service is to allow users to speed read the web (and help other users to do it) - service will be unpopular because people don't like to install extensions, user.js, etc. I don't know any top service, based on extensions. - people don't need it because most of them prefer to watch and listen instead of read. - there aren't easy monetization way of such service. What do you think about vitality of such service?