“For the past eight years or so I’ve been maintaining a single document where I keep all my hunches: ideas for articles, speeches, software features, startups, ways of framing a chapter I know I’m going to write, even whole books. I now keep it as a Google document so I can update it from wherever I happen to be. There’s no organizing principle to it, no taxonomy–just a chronological list of semi-random ideas that I’ve managed to capture before I forgot them. I call it the spark file.”