Cycling Tips has a great interview with Michael Horvath, the CEO and Founder of Strava. If you’ve been around me at all you know I love Strava and use it passionately to track and share my rides as well as my (less frequent) runs.
Strava very smartly filled the hole left by Nike+ for cycling though took it up a notch as well given the upper end athletic focus. The somewhat recent addition of running makes it ideal for the multi-sport athlete and the social features and data viz make it habit forming. Just about everyone I ride with uses it and speaks Strava as well. I recommend the interview and of course the service as well.