Sport can produce quite a lot of data. Runalyze has set itself the task of preparing this data independently of manufacturers in order to make the user understand what her/his condition is at any time. And it's not just for running!
This is a fantastic tool with a bunch of data that helps you track and improve your running performance. I use it to measure my progress, fitness, and marathon shape. The prediction times for races are spot on.
I've been using to analyze my running data. It has pretty impressive suite of analysis, plots and charts.
The app is great, much better compared to Polar and Garmin websites.