This seems to just be the equivalent as game sharing was back on the PS3 (Not sure if you can do that on PS4) except you can do this with an unlimited amount of people and you don't have to give others your account information XP. This feature doesn't really appeal to me sense you have to play the game through one persons account and I assume as your playing the game on your friends account your friend cant do anything.
Although being able to play local co-op basically online is really cool. Are you guys sure this a confirmed feature becuase it seems odd Far Cry 4 would have a co-op feature announced if you can just do the same thing through gameshare.
Survivor Millennial vs Gen X!!







