Given all the hype and venture capital interest swirling around startups like foursquare, Gowalla and Loopt, it's clear 
that location-based solutions are where the action is. Last week, PapayaMobile--an Android-focused mobile social network noted for its casual gaming and virtual currency initiatives--updated its SDK with a suite of new LBS tools, enabling its developer partners to integrate features like real-world check-ins and virtual badges into their own Android applications. No less important, PapayaMobile's new geo-centric features extend across all software incorporating its SDK, meaning the Beijing-based firm's worldwide community of over 4 million users can check-in and interact with each other regardless of which games and applications they're accessing at any particular moment in time. FierceDeveloper spoke to PapayaMobile co-founder and CEO Si Shen about the location services craze, application discovery and the importance of app sustainability.
