Ok then I'll have to ask how those other colleagues or those other IRC people originally heard about those products, ad infinitum.
Things like git and Linux were marketed, they just weren't marketed by professional specialists in return for money. Torvalds was out on mailing lists intentionally promoting his creations. For-profit startups will do this kind of informal marketing too, even technical founders will initially try to talk up their business amongst their circle of friends and associates.
Without someone making a deliberate effort to tell people about new stuff, it's unlikely people will just magically know about it.
That would be true if my thoughts & commentary were available as a product, but they're not. If I said "if you liked what I have to say, get my free or paid eBook that has my thoughts/commentary" then yes that would very clearly be marketing.
This might also be true if my profile or skills were being marketed through my commentary, but I'm anonymous. Others on HN submit commentary and blog posts on HN with the intent of promoting their profile as a consultant or leader. Profit-driven corporations also do this, there's basically no non-altruistic reason to share any of their proprietary knowledge except to market their pedigree to engineers they might hire or customers they might want to impress.
Things like git and Linux were marketed, they just weren't marketed by professional specialists in return for money. Torvalds was out on mailing lists intentionally promoting his creations. For-profit startups will do this kind of informal marketing too, even technical founders will initially try to talk up their business amongst their circle of friends and associates.
Without someone making a deliberate effort to tell people about new stuff, it's unlikely people will just magically know about it.