Hilight Online

You're reading this online right now. Millions of people read articles and obtain knowledge and facts online. Once an article is read, if it's good, people will pass the link to others, but for the most part, the article is forgotten about.
My proposal is this. Create a program that will allow people to hi-light articles presented online. It would probably have something to do with cookies and the browser, and it would work for mostly established sites but quick remedies to problems would arise soon after. Allow people to store all of their read articles in a little file on their computer so that they can go back to it and gather whatever it is they need. This would help us out in both the office and the academic realms.

Where else could a product like this be used? And how would we get the most value out of it?