I know this is a popular belief on HN. But I assume you mean part of marketing that is paid advertising?
Because you know, HN is a marketing site for companies in Y Combinator and Y Combinator itself.
Every landing page you have ever visited is marketing.
Every GitHub README.md is marketing.
There's not a single business in the history of mankind that have made money without marketing. Because they wouldn't be allowed to show or tell anyone they existed.
Wow but that's a nice set of technically true examples to hold up in order to defend people who are literally sending unsolicited email to people.
You know, the people directly responsible for making email suck... and the web... and search engines... phone calls... TV... the mail...
Huh. It's almost like the entire industry does a lot of making things suck.
Maybe if that wasn't the case I'd be amenable to considering some form of marketing as acceptable, but time and time again that industry has proven that being a good citizen is just not something they are willing to do.
Also, landing pages are definitely counted because in my experience you're lucky to even be able to tell what the fuck the product is from the landing page, so bullshit laden are they.
That README.md is often used for marketing in the landing-page sense is just evidence of what I said elsethread: That the psychological damage caused by marketing has embedded itself deeply in our culture and become self-perpetuating.
Nagging emails and 99.9% of ads suck but there needs to be avenues for new companies and products to be discovered. This site is full of marketing, but it is largely balanced out by user power (voting and ability to discuss and criticize).
None. Marketing is an objective blight on human society.