[reckter]

Niantic (The Company behind Pokemon Go and Ingress) would do something similar for events in Ingress: They had a "measurement window", in which they would look at the state of the gameboard in a certain city and count stats (details irrelevant for the story here). The measurement window was 10 minutes long, but they would look randomly at one specific second and count the state at that second. Before each measurement window they would post a SHA hash on their twitter account, and release the string that lead to it afterwards (which was a bunch of garbage and a time like this: "52o5dfeis(})5eidfjsdkdbn 10:03:20 huner54652&e") Worked great for that proof :)

[paulgb]

This sounds very interesting but I'm a little confused by the problem they were trying to solve -- what were they trying to prove knowledge of?