Tapjoy, the small development shop that brought us the incredible TapDefense for the iPhone [iTunes link], has quietly built out an extremely strong toolset to provide monetization options for app developers. Through two strong offerings, they claim to increase ad revenue for free apps by more than 250%. I first met them at the TechCrunch50 DemoPit, and was thoroughly impressed by the Tapjoy platform. First, they aggregate ads from all the major mobile ad networks and serve the highest-paying ad for an app. This method leaves the developer with nigh an unfilled ad; Tapjoy boasts a 99.9% fill rate. Second, they enable developers to sell virtual goods within their apps (such as extra points in Mobster or extra towers in TapDefense) for real money. They do this by providing the user with the option to download an app in exchange for the virtual good. Be sure to read about this later on in the article, because it is truly the most innovative 3rd party platform I’ve seen on the iPhone all year.