While asking for subscription payments is still a popular business model for MMOs, increasingly it's just one option among many. Free-to-play, ad supported, microtransactions, and even straight Real Money Transfers are all being used as viable methods to get people in and playing. Aside from the vigorous debate this issue raises, it's also incredibly challenging to compare games that use subscription-style pricing with free-to-play/microtransaction games. Who counts as a 'player' if theoretically everyone on earth with a PC *could* be playing your game?
Over at Gamasutra CDC Games' Ron Williams attempts to answer just that question. Williams offers that there are actually a large number of data points to track when determining the health of an online title, including the total number of unique visitors (UV) to the game's website each month, the number of new players gained each month, the number of new players that convert to paying players, of the game, and (of course) the total number of paying users for the game. He goes on to offer a few theoretical examples of game data to prove out how, given sufficient data, comparisons between apples and oranges are not that hard to make.