I am always extremely impressed by Gabriel Weinberg's honesty and transparency. He's literally not "selling anything" here. This is just a gift to his fellow entrepreneurs.
Well, he is advertising his company. Like HN, it's a marketing activity, but one that also has a value-creation component, not merely an attention-grab.
That doesn't look or fell like advertisement. An ad would be something like "How we bootstrap our way to 7M searches per month"