Some vehicles have a safety net or barricade that can be set up behind the second row to keep cargo from flying forward in the event of an accident. Kind of looks like it may be designed for that, although I can't find a reference in the owners manual.
At the St Louis auto show I talked with 2 GM spokesmen. One of them said it was for drycleaning...no way...the angle will not allow you to close the door. The other told me it was for hanging plastic bags from the grocery store. Then a customer at the auto show told me it was for the headsets that come with the DVD player...who knows the real answer!
Thanks for letting me know about the headphones...maybe it's the plastic grocery bag theory...who knows. My salesperson at my GMC dealership also told me it was for a suit jacket...hanging the "tag loop" on it.
I love hooks...so I'm sure I can find a way to hang something from there!
If there's one on the other side of the car, you could hang a rod across with the seat down, and load it up with clothes on hangers. Don't tell my wife or she'll think it's more closet space and head for the mall! :'(