The 'Network Settings' provide a setting for this:
Network & Community > Network Settings > General > Show user name. When this checkbox is enabled the user name gets displayed in the community instead of first name and last name.

Under Portal Manager > Tools & Administration > Categories you can create categories and subcategories and assign them to elements like users, helpdesk tickets and companies among many others. Using categories you can create a clear structure and categorisation of your elements - for example by assigning users (elements) to certain industries (categories).
You can create categories and subcategories as well as edit, move and delete existing ones in order to adjust the categories to your current needs.

In the network in the area "Top Groups" groups are displayed according to the random principle. To display featured groups enter the desired groupIDs in the field Featured Groups in the area Portal Manager > Network & Community > Network Groups/Settings.

A tag cloud contains the most popular tags, independent of the element (e.g. blogs, wiki article, documents, etc.) they belong to. The single tags of the tag cloud can be clicked and the matching results get displayed.

Guests are all persons who are not registered and browse the portal without a login.
Regulars are all persons who are registered and who log in with their log in data.

A group can have two different settings concerning the new entrant of members:

1. New members will be approved by the Group Manager
2. Everybody can join the group

With #1 the Group Manager has to approve every single member, who wants to joint the group.
With #2 every new group member can join the group by click, without being approved.

If you want to change that, please click as Group Manager in your group, click the tab Settings and change the selection box New Members.