ZDKP began life as next generation web based guild management system for Goon Squad, the largest Horde World of Warcraft guild in the US. Goon Squad, having grown past 1000 active members and several hundred weekly raiders, had outgrown the game's built in guild management software (which allows a maximum of 500 players) as well as other raid management systems such as EQDKP and nDKP, which were designed for much smaller groups. As a higher level officer in the guild and guild sysadmin, I was tasked with coming up with a guild and raid management system designed specifically for very large guilds with multiple concurrent weekly raid groups.
The Burning Crusade expansion pack introduced a series of features that made the heavy weight loot management / DKP systems of classic WoW increasingly unnecessary. In particular, smaller 10 and 25 man raids (rather than 40) required less central coordination and badges/loot tokens removed much of the randomness that DKP systems helped smooth out. As a result many of the core systems of ZDKP turned out to not be necessary post expansion. The one feature of ZDKP to remain relevant was the raid signup / scheduling system. To date World of Warcraft still does not provide guild scheduling/signup services that work with guilds larger than 1000 players.
For ease of use for new players I have integrated the ZDKP signup system into a module for the forum software that the guild uses to coordinate it's efforts (Invision Power Service's IP.Board). The login systems are syncronized so that forum users can use the signup system without leaving the forums or needing a separate login page. 10 different raid groups now use this system to coordinate over 25 raid events each week with over 100 players in attendance weekly.