The author quickly replied to my earlier comment, and has gained points for that effort. His explanation adds to value of the program.

Many of us can spend significant amounts of time pondering a basic question…are we alone? By googling "Drake Equation calculator," one can find hundreds of basic Drake Equation calculators on the web. We were not first to see the value in further exploring this simple, but stimulating equation. Our implementation is just a bit different -- we've added animation to the results. Thus, this iPad simulator not only performs the same calculation as those useful web-based tools, but it also leverages the iPad's animation capabilities to add a visual dimension to the results. We think this tool will help answer a basic question in a simple, but quite elegant manner. Please share your ideas on making it even better. Thanks and regards - Onomaly