I found this
article on
Gamasutra very interesting. I am a firm believer in using psychology in your game design and even though in the past i have used loss aversion on a small scale, we are now going to experiment with it on a larger scale in our title
Junk: Battles. The idea is that we will create a instant "play now" mode that creates a guest account where no progress will be saved after you logout or close the browser. We will remind the player of this "loss" of progression unless they register now. We hope to accomplish an instant playability option with a high retention of registered users, driving our active vs registered numbers up. Ill keep you posted on our results.