Track Your Happiness is the front end of a research project that seeks to figure out which factors contribute most to our happiness. If you sign up, fill out a 10-minute questionnaire about your life situation, and let the researchers poll you about your mood a few times a day via iPhone, you'll eventually get back a personal report. At first, this seemed a bit intrusive to me, but iPhone users are pretty much glued to their devices anyway, and it's no more trouble than answering a few text messages every day. You can even specify your wake time, bedtime and time zone, so it won't poll you while you're asleep.

The most problematic about the iPhone as a platform is that the study will have no way of determining whether our iPhone contribute to our happiness. It does appear to focus on factors like diet, exercise, financial situation and relationships, though. Each poll is pretty brief. You just position a few sliders to indicate how happy you feel, how self-critical you feel, what you're doing at the moment. Yeah, "making love" is on there, but you'll probably want to wait until you're done to answer the poll, if you really value your happiness. I have yet to use the app long enough to generate a report (it takes 50 polls), but I'm looking forward to seeing what I might find out about myself.