This is an interesting piece that debates the merits of using CSS media queries to build mobile-optimized experiences, tackling Ethan Marcotte’s influential article on adaptive design, “Responsive Web Design”.
For the most part, I agree with Jason’s arguments about the context of mobile and hidden/unused files downloading in the background. These same two points are what led me to argue against handheld CSS in my book, and they remain valid in discussions about media queries, too.
With the prevalence of wi-fi in daily life and the ever-increasing speeds of mobile networks, it would be easy to write off file size and download speed when creating mobile experiences. However, with such news as the elimination of unlimited data plans and this net neutrality thing, I think it’s safe to say network speed, latency, and cost will remain relevant to mobile discussions for the foreseeable future.
For additional reading, see Jeff Croft’s “On ‘Responsive Web Design’ and the Mobile Context”.