Related actions:

• JoinAction: Unlike JoinAction, RegisterAction implies you are registering to be a user of a service, *not* a group/team of people.
• FollowAction: Unlike FollowAction, RegisterAction doesn't imply that the agent is expecting to poll for updates from the object.
• SubscribeAction: Unlike SubscribeAction, RegisterAction doesn't imply that the agent is expecting updates from the object