The achievement system is a new feature in World of Warcraft (introduced in the Echoes of Doom patch) that allows players to track accomplishments and statistics of characters in all aspects of the game.
How does the achievement system work?
You can browse all of the available achievements when you open the achievement window (the default key to do so is 'Y'). Aside from Feats of Strength (see below), all achievements are visible, whether you have completed them or not. When you select an individual achievement, you will receive additional information on how to complete each one and how close you are to completing it. When you complete an achievement, a message will pop up on your screen specifying which achievement you earned. Players in the immediate vicinity and in your guild's chat will also receive a message indicating what you've accomplished.
Can I track how close I am to completing an achievement?
Yes. When you select an achievement, you will see a check box with the word "Track" in the lower left corner of the achievement description area. Check this box to display your progress in the quest tracker area.
What are achievement points used for?
Achievement points are used to indicate how far a character has progressed into the achievement system.
What are Feats of Strength? Why can't I see a list of them?
Feats of Strength are special accomplishments that are either very challenging or no longer possible to complete in World of Warcraft. Some of these include old-world player-vs.-player ranks, certain rare mounts, and special titles. As such, we do not expect players to try to earn them, and they do not provide players with any achievement points.
Why are certain dungeons not showing up as completed achievements when I know I did them but others are?
A: World of Warcraft was not originally designed with the achievement system in mind. While we were able to use specific items in a player's inventory or completed quests to track and award some dungeon achievements retroactively, this was not always possible. As a result, some dungeons must be completed again to get the achievement.
I play a lot of characters, so are there any achievements that will look at my whole account?
Not at this time, but we hope to add account-wide achievements in the future.
Will more achievements be added in the future?
Yes. We plan to build on this new feature and add more achievements in the future.
What is the statistics tab in the achievements interface?
The statistics tab (located at the bottom of the achievement window) contains a wide variety of data on a character to help show the journey he or she has gone through in the game so far.