Ask yourself these questions when considering adding social proof to your app:
The use of social proof in interfaces has become commonplace in many web environments. More sophisticated implementations not only indicate general adoption or preference, but highlight adoptees that are known persons (e.g., Facebook friends). Because of the success of social proof, some sites may over-use the technique and complicate simple interactions. This is why it is important to test the specific design implementations and not simply accept that any social proof feature is beneficial.