I take notes.

Ok, that's not really an existing resource, but a very important one. Every time, I stumble on something interesting, I write down the whole bibliographic declaration and some lines of a summary. At home, I put these notes in some kind of "information retrival system", re-read the source of said information and add some keywords and ideas to the notes.

Obviously, those notes are "wrong", since they reflect my own understanding at any given point in time, including my ignorance and misinterpretation. Also obviously, the notes are invaluable, since they reflect my own understanding at any given point in time. Of course, the notes need some time for (re-)evaluation. I need to know, if I really understood, if I've got some ideas -- preferably with (working (production grade)) code, or if the note just sound interesting, but I didn't have a clue about the meaning.

I recommend that somewhat school-like system. After some time, one can build his/her own resource-repository, which follows ones own habit of information retriveal and processing (also called learning ;-)