I started something like this awhile ago. I was trying to write papers for one of my classes and couldn't find a reference I needed. After about the third time this happened, I figured I ought to make some kind of searchable list of references with summaries about what they contain, and links to the file. I use a google document now, with summaries of books I've read and notes from my classes, in addition to references. What I really want is something like workflowy where I can collapse bulleted points. Workflowy would be fine, but I'd be worrying about going over their limit and having to pay for it, since I have a lot of bullet points. In the meantime, I use google docs' "table of contents" feature so I have that orderly list I want.

I don't put "everything" in it. My general rule is that it has to be either useful, something I'd likely forget, or something interesting. I also link to everything so I don't have to search my history.