Achievements are a great way for WoWWiki users to compete in a friendly contest of badge collection, as well as a way to chart individual contributions. Just like achievements in Warcraft, these are for bragging rights, a way to get your name noticed, and a way to collect a large array of badges to display on your personal page.
A leaderboard keeps track of points earned, as well as most recent badges. Badges and ways to earn them are themed according to Warcraft. They can be as simple as making a single edit, making a thousand edits, or making edits to specific types of pages. Achievements can cover editing, blogging, uploading pics, uploading videos, and more.
If folks are interested, a forum thread would be dedicated to ideas about images, names, and badge requirements.