I used Google docs heavily. I started with a list of 10 uptime monitoring competitors with features, pricing, and weaknesses. I figured out that all of them were charging ludicrous amounts of money to do a simple task like alerts via SMS or email. While they do offer much more features - I realized, after having built a couple of websites that I don't really need fancy features. I also did a SWOT analysis of the idea and where my app would lie in the spectrum, and the amount I could charge to a customer.