i also have a receiver that is gathering dust, as TomTom seperated traffic services for the receiver from Plus Setrvices (I used to get both with the same subscription).
If you have a data plan on a cell/PDA, and you can pair the unit including data services. the Plus Services traffic is much broader in coverage in the US then the receiver.
I do not now where are you were using it, but I see delays in the SF and LA California areas even without an incident all the time. It also gives the delay times per each delay segment, and for the entire route. Not the best system, but it has been helpful.
I wish TT had set it up like a GPS with traffic unit in a rental car I used in Europe 4-5 years ago. It graphically displayed the congestion on the main map, and verbally warned of its location and severity on the route beginning 100 km of more away. And of course, it offered alternative routes very early.