Answer
When an ArcWeb account is opened, a default group is created that includes only your user name. Additional users can be added to the account. When additional users are added, they share the credits on account. They also have access to any custom data shared with them.
The person who sets up the group is the group administrator and this person has the ability to add and remove other users. Administrative privileges can be granted to other so that they can perform the same tasks.
The Manage Users account page displays detailed usage information for the group activity and sets group preferences. The page displays a table that shows each user in the group, their credit limit, credits used, storage used, date last used, and if they have administrative privileges.