I once remember seeing someone dividing all the features of a new product into swim lanes with a column for each functional area of the product and horizontal lanes to represent each development release, with the top horizontal lane being reserved for the unscheduled feature backlog.
The team would then move features down from the unscheduled backlog into the cells below to roughly indicate which release each feature is likely to go into.
Does this technique have a name and can anyone point me in the direction of any links explaining it further?