The People Directory provides a list of all users in your Confluence system. 

If you need to disable the People Directory set the following system properties on your application server command line:

• To disable the People Directory for anonymous users,

 -Dconfluence.disable.peopledirectory.anonymous=true

• To disable the People Directory entirely,

-Dconfluence.disable.peopledirectory.all=true

These two properties are available in Confluence 2.5.2 and later.

Note that the 'People Directory' link will still appear on the dashboard, so you will need to modify the following file to remove the link: /decorators/global.vmd (In Confluence Standalone, this is located in the confluence directory)