The author doesn't really debunk any of what he calls "excuses" when he jumps immediately to Facebook, then Twitter, Uber, Netflix, and Microsoft. Those are companies with <i>huge</i> scale problems. He even says as much, near the end, claiming "the evidence against these excuses comes from some of the largest and most financially valuable companies in the world". Nobody is arguing that performance doesn't matter at those scales.<p>Here's the author's five points, and how at least one of the examples he gives <i>proves</i> the reasons.<p>No need. These companies operate on the leading edge of hardware performance, on purpose. They can't just go out and buy faster hardware, it doesn't exist. Google even builds their own, just to optimize for their uses.<p>Too small. Again, at the scale of Facebook or Netflix, a 5% performance gain translates to an enormous advantage, which leads directly to the next point.<p>Not worth it. Here again, we're talking about saving millions of dollars but only because the systems are so enormous.<p>Niche. Facebook, Twitter, Netflix, and Uber's performance needs are a niche of their own.<p>Hostpot. Here we can get to a specific example the author quotes. "Cutting back on cookies required a few engineering tricks but was pretty straightforward; over six months we reduced the average cookie bytes per request by 42% (before gzip). To reduce HTML and CSS, our engineers developed a new library of reusable components (built on top of XHP) that would form the building blocks of all our pages."<p>So their Facebook <i>does</i> have a hotspot, it just happens that it's a very large spot on a colossal size system.<p>Finally, the author says, "If you look at readily-available, easy to interpret evidence, you can see that they are completely invalid excuses, and cannot possibly be good reasons to shut down an argument about performance."<p>I'm still looking for the evidence.