According to this article it’s possible to play via e-mail… which of course means it’s possible to play it via a forum 8-)
I especially like this suggested game:
WW1 or WW2 campaign
Possibly set in 1914 in the west or east (corps level units), or a WW2 eastern front battle (division level units). We could have teams of players, with a hierarchy, as only one set of orders would be submitted, thus minimising the umpire workload. Teams could organise as they wished, but typically players might take roles, such as C in C, intelligence chief, operations chief etc. They could communicate with each other all the time on plans, analysis etc. without disturbing the umpire’s deliberations. They would not control the individual combat units directly, but rather act as the command staff of an army or army group. The would specify attacks, divisions to be involved, date and objectives. Combat could be resolved by the umpire using a commercial boardgame on the battle, or a PC game such as The Operational Art of War.