[ros-users] multi-threaded nodelet semantics?

Despite searching the nodelet code and documentation, I'm having
trouble grasping the semantics of multi-threaded nodelets.

When would I want to call the getMT* methods for callback queues and
node handles? What advantages do they provide?

What are their threading and locking requirements, versus the
single-thread versions?

Is there any plan for a Documentation review of the nodelets package?
--
 joq