Unlike base Dungeons & Dragons (3.5 Edition), Living Greyhawk (LG) used a Point Based (allocate points to get skills, powers, etc) method to generate ability scores and fixed hit points and starting gold. This was to facilitate convention and worldwide play among a vast player network.
The campaign used dungeons-dragons-3rd-edition rules till 1st of March 2005 - all characters played from that day on needed to be dungeons&dragons 3.5 compliant.
The administration of the campaign and the player's characters was done by a team of volunteers for each region - called Triad - and a group of RPGA members "The Circle of Six".
Most of the scenarios for the campaign were written by players within the campaign. The scenarios and the outcome of a scenario - success or failure of a group of characters - often had direct impact on the political situation in the campaign setting.
The campaign started with the given setting of the World of Greyhawk presented in various sourcebooks in 590 CY. As the players/writers/triads developed the situation over the run of the campaign, the whole campaign can be seen as a special form of fan-fiction. Most adventures, regional gazetteers and background material written during the run of the campaign is considered non-canonical.
There were several types of standard scenarios in the campaign that could be played at conventions and by RPGA members at home. Some were open to all players - COR - Living Greyhawk Core Adventures, some were limited to players in a certain campaign region - Living Greyhawk Regional Adventures, or certain group of regions - Living Greyhawk Metaregional Adventures.
In addition to the standard scenarios there were several types of special scenarios - some were only offered for play at certain big conventions like CORS - Living Greyhawk Core Special Adventures, some were one shot adventures at regional conventions and some were custom made scenarios for one or a few characters.
Standard scenarios of the campaign were normally offered at several difficulty tiers and played at a tier according to the levels of the characters brought to the table.