Or your link could be about inequality, net neutrality, spying, self-improvement or a hot language/framework. HN has pretty predictable interests.
I seem to recall that the same thing happened when HN had a fling with Bayesian statistics...last year? Two years ago?
I think it's a necessary consequence of having a large, broad technical audience that really enjoys investigating very narrow niches. Eventually even the people on the 'edges' of that topic's appeal want/need to find a way in.
Going by reputation, the dragon book would be an example of the opposite: Very in-depth, but with horrible writing.