One possibility is to give your service so that other applications, via your API, can provide game mechanics they believe would be relevant. Then Darwinian sel

One possibility is to give your service so that other applications, via your API, can provide game mechanics they believe would be relevant. Then Darwinian selections of which game mechanics work out. Ie. Focus on what your service and its core benefit(s)/reward are about and outsource to your ecosystem the game mechanics layers.