Reputation systems are like social networks, they are only as useful as the amount of people in them. Rapleaf, one of the more visible reputation systems, is now displaying which social networks a person belongs to. You can use this information to quickly learn about a person before interacting with them in the real world. Useful stuff.

I got to know Auren Hoffman, consummate Silicon Valley networker and Rapleaf founder, when I was advising identity aggregator Opinity on ways to leverage the value of aggregated social networking data. A marketers dream, really.

Rapleaf + Cardspace + identity authentication = killer app. Distributed transparent silios for the data, managed via Cardspace with API connection to partners like social nets and blog comment management. Who’s going to built it?  A few have tried, nobody close to putting all the pieces together, talk about a wide open opportunity.

Rapealf is hiring offering a $10,007 bounty for software engineer referrals we hire. Inquire at jobs@rapleaf.com.