I had an idea somewhat like this a while back, but never worked out how to do it. Basically I wanted to "log anything" so basically you'd enter a quantity, a unit and what it was... and then later I'd figure out a way to make graphs and charts. This is clearly different, and the execution is good. I was a little confused by the interface early on, so some tooltips might be in order. I also wonder if a "date" type might make sense. I wanted to add a date to my list of items - maybe it would be a due date, or if you're listing things that took place, you'd like to add that to the list. Or just record when you had an idea that you want to add.