When reading information on the web or through my feedreader, newsbeuter, I use Zim (http://zim-wiki.org) to take notes on whatever I think I may want to refer back to in the future. I place notes in an appropriate category, apply a datestamp, and optionally add some tags.

Zim automatically indexes everything, so when I need to find out how to apply that cool Rails trick I read about 3 weeks ago, it's easily found.

So, yes, output is very important, and taking notes helps me get a lot more out of my online reading than if I simply tried to make my brain act as a sponge.