Have you ever wondered if there's more of a purpose to the yellow sticker with the 25-digit product key than to sell keyboards by wearing out your old one? Actually, there is -- through a complicated, flowcharted process that ranks somewhere between alchemy and string theory in terms of the number of people who have mastered it, the process that prints those yellow stickers also generates a "hash" -- a scrambled summary -- of each, and a list of hashes gets sent to me (actually, I have to pick it up on CD from a Microsoft building) whenever a batch of stickers gets printed. This list of hashes then gets sent to Gamespy, which provides the online service for Halo PC. They make sure that only people with real copies of the game get to play, and only one person per key at a time. Aside from deterring piracy, this helps our legitimate players by allowing you to ban players from your servers, knowing that they have to pay for another copy to get back in.
What does this have to do with stats? Well, I just logged in to the key-admin site over at Gamespy to deal with a new batch of yellow stickers that was just printed, and found that they keep a tally of how many unqiue (and legit) product keys of Halo PC have played online in the last 30 days. Ready?
This is pretty impressive for a game nearing its 4th birthday. Incidentally, this includes regular and Custom Edition users, since the CD key is the same across both versions (but it only counts each user once regardless).