Put players into groups such as whitelist jobs or moderation groups. These allow you to set up custom roles that group members can have, and then configure what they can do within the group. Groups have their own independent modules, check Group modules.
Add members, enable applications and let players apply to any group
Define max members in a group
Add leaders to a group and let them run it themselves - answer applications, add new members, give them roles, etc.
Create group Pages, such as group rules, requirements for applicants, etc.
Create blog posts with group Blog module
Use Action logs in each group
Automation module integration