We like to view the fans of the Macy's Thanksgiving Day Parade as a community. Like any well-run community, you must have those who enforce rules and keep the community under protection. The administration of a wiki is typically run by its founders and a select team of individuals who work together in the interest of maintaining certain aspects of the wiki. These duties include cleaning up areas of the wiki that regular editors don't have access to, disciplinary actions, mediating contested discussions, and a general interest in the overall quality and reputation of the wiki.
A bureaucrat is the highest position one can hold when operating a wiki. These users are extremely trusted, and are often organizing ways to expand the wiki's appeal and community.
Like the bureaucrats, the admins hold a large amount of power and assist the bureaucrats in their everyday duties.
How do I become an admin?
As mentioned above, both bureaucrats and admins have a large amount of power when it comes to controlling the wiki. Admins are rarely added to the wiki. There are exceptions to be made when we know a user for a long time, and have done work with them. There aren't that many admin powers that really matter -- deleting pages and blocking vandals, which is important but not super exciting, and customizing the skin, etc. All of the interesting stuff -- building articles, adding pictures, talking to people -- is available for everyone.