You've probably heard people say we're living in a "post-PC world." What does that mean for web developers? It means that 30% to 50% of your website's traffic now comes from mobile devices. It means that soon, desktop and laptop users will be in a minority on the web.
How do we deal with this tectonic shift in user behavior? We've moved beyond the era of m-dot or t-dot hacks, into one where responsive and adaptive design techniques rule the day -what the W3C calls a One Web approach. The key part of the W3C's recommendation is that "One Web means making, as far as is reasonable, the same information and services available to users irrespective of the device they are using."