Yes, all positions at the OTW are unpaid though I understand your confusion. The differences between "staffer" and "volunteer" are based on the level of engagement and complexity of the position.

For example, tag wranglers and translation volunteers are large pools of people, and they generally create their own schedules and work fairly independently compared to staffers. Staffers may have a leadership role of some kind (supervising volunteer pools, for example), are expected to attend committee meetings, may be 'on call' in some way, and work in conjunction with other staff or committee chairs as part of their job. Depending on their role they may also be in a position to interact with other committees and get a much broader view of the OTW's workings, which is one reason why to be eligible to run for Board one must have served as a staffer for many months.