Impressive number: The 200m estimate of Wi-Fi units shipped in 2006 is due, in part, to the increasing prevalence of Wi-Fi as a prebuilt option--nay, necessity--in laptops, music devices, and gaming systems. The Wi-Fi Alliance noted today that the Zune, Wii, and PlayStation 3 all feature Wi-Fi built in. Odd that the Xbox 360 does not; Wi-Fi is a $100 add-on that might cost $10 if integrated. (Consumer electronics are often cost times 10 for separately sold items.)