I would be very interested in single counters in game, which can be incremented by all players without running into write conflicts.
I my example, I have a quiz game and I want to track how often a question has been answered right or wrong. So I would need (in my case) two integer values associated with the question id. The players can increment by a given amount. No matter how many players try to increment at the same time, the result should still be correct.
The same could be implemented for data scoped for players or groups.