Or he had somewhat passive success with some SEO/other tricks and excitedly shared them to a good feedback loop. Works as marketing but I doubt marketing was his first thought.
I've had to grow traffic for sites before. Generally, even if its good content, you have to put some effort into driving traffic to it. Which is marketing. At which point, you are doing it to market something. The first thought is marketing.
I have had profitable side projects but I never talk about them on HN or other sites.
Self promotion is inherently about marketing and even at the start that is precisely what he did.
Explains how it wasn't necessarily his first thought. In the beginning, it was HN comments where the first thought is more sharing content you feel is relevant, or the gamification of karma.
I'm responding to you and at no point do I feel like I am marketing "prawn" or anything I do online. I'd use a relevant username for one thing!
The fact anybody cares about this at all is a testament to Patrick's masterful manipulation of online audiences.
The fact you believe "I doubt marketing was his first thought" is why it works so well. You don't realize you're being manipulated into internalizing the personal brand of someone more clever than you.