I do this ruthlessly. I skim the first part of many articles, and do the same for books, which I have in almost constant supply from amazon.

I wrote a system for myself (called Mnemo) that I used to catalog and cross reference stuff. I can tag things, and search by author, keyword, whatever. This is useful not only for going back through a topic I'm interested in, but also because while I'm reading I can ask myself constantly: would I put this in Mnemo or am I spinning my wheels?

Maybe I'll release Mnemo and see if it works for other people.