The answer to this question is "sort of yes" and "sort of no." Two Facebook users can both use AppDog on a single device. However, the two users will have to share the available offers. To illustrate, let's say that you and your brother share an iPad. You login to AppDog, download GroupMe, and earn 10 Bones. Later on, your brother picks up the same iPad and logs in to AppDog with his Facebook account. The GroupMe offer will not be available to your brother.