At Spark Capital, we have always believed that one social graph was insufficient. 

And we have put our money where our mouth is investing in Twitter, Tumblr, Foursquare, Boxee, Svpply, Exfm and others. A passionate focus from the founders + targeted engaged community is something we care a great deal about. 

We like it even better when the service is targeted directly at the user

Boston based RunKeeper is a service that represents all of this goodness.

Jason Jacobs is a man on a mission. He’s completely possessed and his passion is infectious, as anyone who knows him will tell you. 

Jason and his team built one of the first iphone apps just as the as the app store launched. They were focused and built RunKeeper as the best way to keep track of your fitness and wellness. Today they have over 6 million users

The vision was always bigger than an app. Recently the company launched the Health Graph API so third party apps and devices can integrate. Getting the platform in the hands of developers is smart and they are seeing lots of support from the community. 

I’ve also been a big fan Runkeeper as a user.

Today, I’m thrilled to announce that last week we became investors and led a new round of financing. We were joined by Revolution Ventures (founded by it’s Chairman Steve Case and AOL’s cofounder) and existing investor Bryce Roberts at OATV. 

If you haven’t already, give RunKeeper a try!