Tapjoy and PapayaMobile are teaming up to create social recommendations of Android apps on offer walls in the Beijing-based company’s gaming network. The interesting thing to note is that PapayaMobile used to partner with rival provider Adknowledge on offer walls and it looks like the company is switching companies.

PapayaMobile, which says it reaches 35 million users on Android, will now show Tapjoy offer walls with a little bit of extra detail — like whether the game is popular on the network, suddenly hot or whether a user’s friends are playing it.

These are the kind of more targeted recommendations both companies will have to offer as more powerful players like Facebook threaten to create new and competitive viral distribution channels on iOS and Android for mobile developers.

The recommendations based on friends’ playing habits from Tapjoy and PapayaMobile will be anonymized to protect privacy — an interesting choice considering that Facebook doesn’t do this. The recommendations will start appearing at the end of the year. Developers have to integrate SDKs from both companies to make them appear.

Tapjoy is arguably the largest network for incentivized installs where players can download apps in exchange for virtual currency in their favorite games. They used to be dominant on iOS until Apple clamped down on the practice, sending them to Android. PapayaMobile, likewise, initially tried to build a network on iOS until it became clear that Apple’s rival Game Center, the company’s control over payments and then Android’s openness were going to make Google’s mobile platform a more hospitable environment for a third-party gaming network. They recently returned to iOS after a long hiatus.