EPGP explained

[Zazar Main]

Purpose
Provide a fair way to distribute loot based on specific and transparent criteria. Some features of the EPGP system:

*Share loot based on participation
*Eliminate incentives to horde or compete with other members
*Reward good etiquette in raids and in the guild
*Reward boss kills, even if loot is disenchanted
*Encourage attempts through all the wipes for new bosses

What Is EPGP?
It is a way to distribute items in 10/25-man instances based on a "Priority" system. When items drop, each item is given to the bidding player of proper class and spec with the highest Priority. There are no rolls and there is no DKP to "spend", although your Priority functions similarly to the way DKP does in a fixed-price system (person with the most gets the item).

EPGP means Effort Points (EP) / Gear Points (GP). EP is awarded for your actions and increases your Priority. GP is the value of the loot you've won and reduces your Priority. Your Priority is your EP divided by your GP, so when your EP goes up, your Priority goes up and when your GP goes up, your Priority goes down.

Unlike the DKP systems in which you "bank" points and spend them on gear, you instead have two running totals -- EP and GP -- that both go up. Because Priority is a ratio of the two numbers instead of subtracting one from the other, EP is not tied to gear values and can be awarded for anything you do that the guild values.

GP is the simplest part of the system. Every item's GP is calculated from its item level and slot. The EPGP Wiki explains the formula to calculate GP. The EPGP addon will show you the GP value of any item in-game so you can see the GP of your own gear, gear in AH, other player's gear, and gear that drops off bosses.

EP is awarded as "Earned EP" during raids and as "Bonus EP" for other actions you take. The types of EP awarded and their relative values are set by our officers based on guild priorities. Obviously downing bosses earns EP, however not all bosses are equal. New bosses earn more EP than farmed bosses.
For a detailed explanation of the system, see EPGP Wiki.