Permissions ... a really huge field, where you can discuss a lot (and more). In every system (not just SharePoint), permissions are needed to give users specific rights or just to secure specific content / documents. We´ve talked about the need of permissions and the roles users can receive in a former article.
One side is to grant users with specific roles / permissions, but the other side is to keep track of all groups. If you are an administrator and want the users to get a quick overview of given rights, you may want to create a cockpit-like page, where the "Site Users"-web part is used to provide this information.
The "Site Users"-web part can be configured to display the users of just one group or all users within the web. The web parts can be placed on a page from an administrator and all users can get an overview of the provided information.
The users don´t need administrator-privileges to get the information into the web part.
Steps to do:
With the given example, it will be possible to create a page, where you can have multiple instances of the "Site Users"-web part. Each web part can display a different group. This could be helpful, if you have multiple groups with multiple roles in your site.
Hint / keep in mind:
SharePoint groups have different options of displaying the memberships of users. If you switch into your group´s group settings and look at following settings, you will see these options.
In most cases the settings provided within the screen should be the setup to go.
If you switch back from "Everyone" to "Group Members", some people may see a blank web part on your page (they won´t see the members of this specific group). This is no really big problem, but you have to keep this settings in mind.