If you beef up your World of Warcraft game with add-ons, the free Curse client can take a great deal of the frustration out of maintaining and updating them.
The app automatically scans your WoW add-on folder and determines which have available updates from the vast add-on library at Curse.com. It unfortunately can't maintain add-ons available from other sites, but the client allows you to click a button to quickly update any add-on it does know about.
You can also search for and install new add-ons from within the well-laid-out client, and open any given add-on's Web page or change log. With the free version of the client you'll have to update each add-on individually; a paid premium client allows for updating everything at once.
The Curse client can't cover all your add-ons, but it can make it much easier to handle the vast majority that are represented on Curse.com.
Note: For a beta version of the client available for Macs, head to the Curse download site.