[skydhash]

> Building different versions of your site for different widths is not a solution.

I think about it as building different sites for different form factor. What you do on a phone is different from what you do on a desktop. Or a tablet. I don't like using the amazon website on mobile because it's so cluttered, when what I want is usually searching for a product, or checking my cart for a product. I'm not managing my account in there, nor do I want alternative recommendations.

[wizzwizz4]

What you do on a phone is different from what you do on a desktop. What if I want to do the "mobile" activities on a desktop, or zoomed in enough to trigger the viewport changes? What if I want to do the "desktop" activities on a mobile? If you want to make a separate mobile site, make a separate mobile site: don't use effective screen resolution as a proxy.