The Mirrored Road into the Interior

Quick though. Self regulating system for keeping an easter egg hidden in online game with large player base. Easter egg provides special item, Item's effectiveness (announced on acquisition) varies with the number of people who posses said item, on the scale of X/(log(n)) where X is the adjustment to whatever it adjusts and n is the number of said item wandering about the world. This won't keep the egg from leaking, but it might slow down the leak. (Eventually someone will value spoiling the easter egg more than they value the bonus.) Item should give significant bonus, possibly of a type that is uncommon or absent in the item sets in the game. Also possibly give it a visual effect that decreases with the number present in the game. (Like WoW's weapon glows, except the glow gets dimmer with each new copy.)