rlange - 1:19 pm on May 8, 2012 (gmt 0)
I really like the concept of responsive web design (RWD), but there's an elephant in the room that very few people seem willing to even acknowledge when promoting it: bandwidth. A lot of your mobile users will have bandwidth caps. You need to think about them.
You also have the issue of higher resolution images needed for display on a full-sized monitor. You don't need all of that data on a smartphone, but there's no way to swap out that desktop-optimized image for a mobile-optimized image.