Guild advancement

Guild advancement is a feature announced during BlizzCon 2009 which allows guilds to level in a way similar to characters. There are currently 25 levels for a guild to progress through. Experience towards level progression is gained through guild member participation in dungeon and raid boss kills, battleground victories, Arena victories, and profession skill-ups. To qualify for guild XP, a raid or PvP group must be composed of at least 80% guild members (with some exceptions, see exact numbers below). Participating in any of these activities will also grant players reputation with the guild, which allows them to purchase unlocked guild rewards like heirlooms, recipes, pets and mounts. Originally, there was also going to be a guild currency and a guild talent tree system, but they were simplified (guild talent trees became a set of linear guild perks without exclusive choices, and guild rewards are purchased with gold instead of an additional currency type).

Earning guild experience
A guild is able to level up to level 25. Advancement in levels is done in a manner similar to player characters: a variety of tasks lead to earning XP which counts toward advancing to the next level.

Activities which earn guild XP include:
 * Boss kills in a raid or dungeon in which most of the party is from the same guild (see below)
 * Rated Battleground or Arena wins in which most of the party is from the same guild (see below)
 * Completing quests / daily quests that reward experience

For each level, the guild is awarded a special perk. These perks will add convenience to guild-related activities like raid-wide resurrection after a wipe or raid-wide summons.

Size of party to qualify for guild experience
The top left of your minimap will show a small flag with your guild logo indicating if your instance qualifies for Guild achievements. Hovering your mouse over the flag indicates the status. If it isn't showing the flag then your group won't qualify for guild XP/rep.

Raid and Dungeon boss kills
Guild xp for boss kills is scaled on a few factors:
 * Boss level
 * Normal / Heroic (Heroic dungeons have a 1.5 multiplier on all guild experience earned.)
 * Number of guild members present (more xp for raids, since they are limited to once a week)

Arena victories

 * Amount of guild members present
 * 2/2
 * 3/3
 * 5/5

Rated battleground victories

 * Amount of guild members present
 * 8/10 - 10 player rated battleground
 * 12/15 - 15 player rated battleground

Guild XP & guild reputation caps
The daily cap on guild XP is 6,246,000 (i.e. 6.246 million) XP. The guild's current XP is listed in the Guild Tab, which also shows a meter of how close your guild is to the daily cap.

The weekly cap on Guild Rep is 3,500 rep. Thus it takes just over 12 weeks in a guild to reach exalted, provided you have enough guild activity each week to reach the cap.

Although present at launch, Blizzard removed the ability of guilds to gain Guild XP from completing achievements in a hotfix deployed soon after Cataclysm's release, leading to the belief that every guild that hits the daily XP cap every day would eventually reach guild level 25 on the same day. The daily cap on guild XP is removed at level 23; during the last two levels experience gain is unlimited. See the table below for the time required for each level (assuming the cap is hit each day).

Guild perks

 * Once a guild hits level 23, the daily cap on experience gained is removed.

Guild items and guild reputation
Participating in various activities earns members Guild reputation. Members can buy special items (with gold) based on their current reputation level.

Guild achievements
Guilds will also be able to gain achievements for killing bosses, obtaining a certain membership demographic, and other activities. Some achievements will reflect achievements already available to players.

Achievements mentioned at BlizzCon include:
 * Clearing a raid instance
 * Having a Grand Master in every profession
 * Obtaining a legendary item