NVIDIA is panicking now, since Radeon is the new gaming card. H-hey, guys! Come back! We got a cool demo! Two weeks before everybody else! Also, the full release has been out for like a year.
Portal has not been out for "like a year", not even 6 months. You also must not have noticed nvidias actual problem they've had lately, where they can't produce enough chipsets to match the demand for the 8800gt that constantly sell-out from stores at a cost ABOVE nvidias msrp. What do they have to panic about?