"Responsive design isn't always the answer. Sometimes a dedicated mobile site or app is. Although when starting a project fresh, it often is. Plus, Google likes it and working with a single code base is nice."
"This error-recovery behavior ignores a chunk of your stylesheet that is small enough to prevent one error (or new feature) from wrecking the display of your page, but large enough that the behavior is predictable and friendly."
"There is a (fairly solid-looking) proposal in CSS4 Selectors called :nth-match() that should allow authors to set up a condition where list items 4 and 6 get selected—for example, :nth-match(odd of li:not(.skip)), unless of course the syntax gets changed—but that’s for the future."
"PageSpeed Insights is available as an open-source browser extension for Google Chrome and Firefox. Webmasters and web developers can use PageSpeed Insights to evaluate the performance of their web pages and to get suggestions on how to improve them."