On sentiment analysis. I have a friend who posted a lot of status messages that indicated mood. Often on top of the world, often raging about someone or something. I took the time to put 1 year worth of comments into a spreadsheet and gave them a 1-5 score for what I thought her mood was. I wanted to run an Fourier analysis on this to see if a roughly 28 day signal was apparent, but the data was sparse and I didn't feel like finding a way to do it. Can you do that? Can you do it for other people and not just yourself? That would cause quite a stir. FWIW the person I wanted to analyze is probably bipolar, so her posts were always very extreme and that's what got me thinking. My interest was purely science (and humor) but others might want to use/abuse such information.