This is a pretty condescending article. I mean, it's certainly true that your average Silicon Valley engineer or entrepreneur is of far above average intelligence, but things like knowing what a URL is isn't a good way to measure it. For the literal argument of this article, it's a specialization. I'm sure there are military commanders that are strategic geniuses who wouldn't immediately know how to get to special characters on the iPhone, or highly skilled pilots who can't answer the question, "what's a browser?" accurately.
These are pieces of topic knowledge, orthogonal to the question of "smart".
All of this said, having worked in consumer internet, I totally agree that the vast (read: vast) majority of internet users are absolute retards (or at least play them online).
I think this is a case of "flamboyant headline; reasonable article". He doesn't really argue in the article that people are stupid. It is implied by the headline, but that is clearly just an attempt to get pageviews. The actual content of the article is quite reasonable, and true.
While it would be even more reasonable for him to include a paragraph about how other people probably feel the same way about us with things like "social skills" or what have you, that would be off topic, and overly pedantic.
These are pieces of topic knowledge, orthogonal to the question of "smart".
All of this said, having worked in consumer internet, I totally agree that the vast (read: vast) majority of internet users are absolute retards (or at least play them online).