Sorry, I should have read the parent post more carefully. However, I still think that's it's valid to compare Chrome and HN strictly on "freeness" regardless of whether or not they're the same kind of product.
We're talking about advertisements and the advertisement's only one one page. The scope of the actual advertisement is roughly the same as it is on HN. The fact that an advertisement in the default tab of a browser is likely to have more viewers is irrelevant.