The new service, which will cost $4.99 a month (or $19.99 for the first year, if you sign up during their introductory special), provides tools that, according to Jacobs, "drive ongoing improvements to your fitness performance," i.e. help you run and walk better. With its enhanced charting capabilities, you can track how your pace and distance improve over time, compare your calories consumed during workouts, and create analytic reports that estimate how different factors like pace and elevation affect your distance during runs.
Jacobs emphasizes the utility of tracking performance details over time. "It's the Hawthorne Effect," he explained over the phone. "You've got to measure yourself in order to improve. Plus, RunKeeper adds a sports element to the process making it fun to compete against yourself and the entire application is very social. You can share your profiles and automatically post your runs to Facebook. Last month, we got more inbound traffic from visitors looking at their friends' shared RunKeeper runs on Facebook than traffic from Google search."
The new FitnessKeeper service builds on this very human desire to analyze and share performance details by adding new ways to view and use fitness data. RunKeeper [iTunes link], already has a strong, loyal following. TUAW reviewed it positively last November. Although pricey, this new web feature may be exactly the thing the fanatical runner inside you has been looking for to complement the existing iPhone app.