I just want a place I can keep track of the many projects I'm "working" on at any one moment. My attention seems to cycle through a semi-fixed list of topics and when I come back to a topic I don't always know what's going on. Plus even if I don't have any readers, I'd like to document the things I figure out so random googlers can get a leg up.
Also, I need a place to articulate the solutions I find to problems. No matter how blinding the insight or life-changing the epiphany, I usually forget how I solved a problem the first time around.