(from http://arxiv.org/pdf/1210.1173v1.pdf ) However, in certain cases the players may adapt their strategy depending on a piece of advice. The latter is delivered to all players by an advisor. This opens the possibility for the players to adopt correlated strategies, which can outperform independent strategies. There are various forms that advice can take. For example in the case of correlated classical advice, the…
I've since accepted they're probably really important and non-obvious from a more rigorous and formal standpoint. Maybe this discovery is the same way.