"Would benefit, eventually, at some point when butting up against resource limitations if they're advanced and do this for a while and no one's around to point this out of them on code review" != "everyone needs to know"
I think I get what you're saying here. You don't "need" to know this to write code. Which is true - heck, you don't "need" to know how a tcp/ip connection works, or how disk storage works. But one day you might.
When you put fuel in your car and you turn the ignition and step on the gas, the wheels move. So all you need to know is where the fuel goes and how to turn the ignition and where the gas pedal is. But one day, I guarantee you, the wheels will stop moving.
When your boss storms up to your desk and says "Why aren't the god damn wheels moving?! We're losing ad revenue every minute!!", I hope Code Review Guy is around to tell you how fuel injectors work.
You know, I have a really hard time imagining a situation where your boss storms up to your desk and says "Why aren't the goddamn wheels moving? We're losing ad revenue every minute!!" and you reply "Aww goddamn, I forgot to account for DRAM refresh cycle."
There's knowing how fuel injectors work, and there's knowing how copper crystal in the wire admits an energy band for free electrons.
The point isn't to know the answer to every problem. The point is to be educated enough to even have a guess as to where to start looking for the problem, and then start trying to figure out the answer.
I think there's a big difference between "read once" and "know". When some people say a fact is "known" they mean strictly that you are able to recall that fact in toto. That is probably overkill for a Web programmer.
After you read something once you don't strictly know it. However if you run into a related problem down the road, you have a good chance that you can remember enough of what you read once to put a Google query together and find the original article.
After thinking about it a little more, what they probably mean is that while most programmers will forget most of what they read here (because they don't use it day-to-day) it is reliable information that will help shape their intuition about how memory works. That is probably what they mean about every programmer and this article.
Every programmer ought to read and test their intuition about how memory works against the content in this article. If they are surprised by something they read, they have the chance to adjust their intuition so that it is closer to the truth.
