No real p-zombies exist in any probable way, but a lot of ideas about them have been suggested. This map is the map of ideas. It may be fun or may be useful.
The most useful application of p-zombies research is to determine whether we could loose something important during uploading.
We have to solve the problem of consciousness before we will be uploaded. It will be the most stupid end of the world: everybody is alive and happy but everybody is p-zombie.