Within a Vanilla Forum powered community, there are a two ways to differentiate members: Roles and Ranks.
Roles are typically used to group people based on their permissions and the role they play in the community. Common Roles include: members, moderators, staff members and administrators. You can create different Roles to fit your needs and modify the permissions given to each Role.
Another way to differentiate users is with Ranks. Ranks are usually used to denote seniority or status to the rest of the community. Rank levels can be assigned or can be earned by acquiring reputation points.