A few days ago, I built a simple command-line app that uses the built-in OptionParser library to parse command-line arguments, called Spydec. And then I wrote a minicourse about it for you. Spydec makes it simple to compile data about industries/markets for competitive analysis. It makes it super easy to gather the most important data such engines use to rank websites. Find out how to build such an app, and distribute it as a gem.