Group managers have the role of Group administrator, and permissions that go with that role. This role grants permissions gaining access to areas of this website out of bounds to most members. In most cases, the GM has final say over who is allowed in a Group. In a nutshell, the role of Group administrator allows GMs the ability to administer their group(s), any way they see fit.
Besides having the roles and permissions to administer their group, GMs also have the ability to give members in the group their own roles and permissions. When a group gets too large, a GM is going to need help. Need one or ten moderators? Assign group members the role of moderator. Does your group need editors, authors, or proofreaders? Assign members these roles as well.
The roles mentioned above start with default permissions, customized for most situations. However, a GM is not limited to these choices. GMs have the ability to change default permissions and create entirely new roles, each one with their own unique set of permissions. Finally, a GM can assign other members the role of GM, either to take over entirely or just to help lighten the load.
In Private groups, the only way to join is through invitation from a GM, (or at least their final approval). Private Groups allow a GA to add members they approve of, and ban those they do not. When groups are public the GM does not have this power. In public groups a GM may simply block individual members from participating, which is still power enough.
There are many more things a GM can do by themselves, and all can be done without the need to call on Admin.
Compensation for Group Managers
At this stage of development Group managers are not compensated for administering their Group. For a Group to get off the ground someone has to administer it. However, I do see a day when a GM could be compensated if their group brings in revenue. Before that time comes, if it happens, Group Managers who contribute projects will still get compensated, just like everyone else.
Benefits for Group managers
In the short run, we hope to make the role of GM not only fun but also enlightening. In the long run, we hope to find out who has the right stuff, and who needs help to achieve it. All this, on top of the satisfaction building what we each feel is important, or the profits we earn, when our results start coming together.
To those who become Group managers, know this: A GM is a natural choice to become manager of the department they helped turn into reality. Whether you become a department manager at that time, or take up some other position, for all practical purposes you are already hired. It stands to reason. Placing yourself in a good position to breakout with the rest of us, could put you in prime position, when that breakout occurs.