In the article, Dr. Nielsen has this to say about Responsive Design:<p>> JN: Because I was writing about user experience, not implementation<p>This is <i>exactly</i> why so many people took issue with Dr. Nielsen's statements: he did speak about implementation.<p>Some examples, straight from the alert box:<p>1. "Build a separate mobile-optimized site"<p>The fact that the mobile-optimized site needs to be separate is clearly about implementation. If the argument was made that there needs to be a separate experience for mobile users, I think nobody would have disagreed, but this is not what it says: it says there need to be two completely distinct sites.<p>2. "If mobile users arrive at your full site's URL, auto-redirect them to your mobile site"<p>Again, redirection is an implementation detail. Why does the URL for the mobile-optimized site need to be different from the regular site? Why not serve different content to different users at the same URL? Why not do this using CSS or JavaScript? How is having a separate URL beneficial for the user experience? This is not mentioned.<p>As it turns out, there <i>are</i> usability issues in having separate URLs for mobile and regular sites. For example, if I email or bookmark a link from my phone and later open it on a desktop computer, I get the wrong site. That's not to say that there is no place for separate mobile sites (especially when the mobile use case is clearly different from the desktop use case), but this an entirely different story.<p>There is plenty of wisdom in Nielsen's words, but the Mobile Site vs. Full Site is a moot point. The argument should have been "create a separate mobile-optimized experience" instead.