I agree with Aaron, but I don't think he'd go this far. Programmers concerned with performance need to understand caching and the cost of a cache miss. That's about on the same level as PB and his read heads. The level of detail in this article goes well beyond that and is unnecessary.
I wouldn't have used these words (that too in the home page): ecommerce, web2.0, Ajax, HTML, CSS, rich text editor, admin. Is it just for web programmers?