With respect, it's a compelling app but it's easy to give something away. The real question is how to wrap a revenue model around your offering. If you base advertising on my on-line behavior it may be viewed as too invasive. Another key attraction is that it doesn't interrupt me when I am in flow, so you are probably limited to presenting ads during the analytics so that I am not interrupted when I am actually working. You've done a good job of addressing privacy concerns so far, but a local app would be even more secure: why not offer a version that competes with http://www.timesprite.com/ the attraction for me is that their revenue model is clear and I can rely on them being around for a while. And I would be glad to pay $40/yr for rescuetime as is if I knew that would allow you to persist in your current privacy model. Your situation is unstable until you get to at least cash flow positive. It's a great app, but I would worry a lot more about adding some kind of paying customers instead of more free users.