The closest thing to that that I'm aware of is barnacl.es
That site is aimed at entrepreneurs, with a particular focus on people who are bootstrapping instead of pursuing VC money. A lot of the discussion there tends to involve marketing, although the site isn't necessarily aimed at marketers per-se.
Another one that this reminded me of is "The Backstory" (http://talk.andrewchen.co/) by Andrew Chen (from Uber). It deals a lot more with marketing and growth but is still a great resource for entrepreneurs.
There is a really great Slack team for SEO & Marketing called Online Geniuses (https://onlinegeniuses.com/). It's not really "HN like" but it's a really great community.
That site is aimed at entrepreneurs, with a particular focus on people who are bootstrapping instead of pursuing VC money. A lot of the discussion there tends to involve marketing, although the site isn't necessarily aimed at marketers per-se.