Whether you need to keep a closer watch over your wiki's users or you need to raise their privileges, these extensions were built to help manage all things related to the user.
While allowing anyone to create an account may be the nice way to go, sometimes, you may want to limit who has access to your wiki. The ConfirmAccount extension makes it so that any accounts created need to be approved by the sysop/bureaucrat accounts before they are activated.
This extension has quite a few configuration options available to you, from determining the minimum word count for a user's biography to how long an inactive account can exist before it is automatically rejected.
If the EditOwn extension gives your users too much freedom, then EditOnlyYourOwnPage is the extension for you. With this installed, users can only edit their user page, talk page, and subpages of them. That's it.
Of course, your sysop isn't prevented from editing pages.
Everyone likes to be recognized. So if you are not one of those wikis with EditOnlyYourOwnPage installed, you may want to bring attention to those users who contribute quality content to your wiki.
This extension comes with a great piece of documentation that explains how to use the four reward techniques:
Amount of References
Most Viewed Articles
Rating of Articles
Recommender System