Rand Fishkin and Dharmesh Shah started Inbound.org - http://inbound.org/ - to be a similar community for online marketing. The links posted are pretty good, but so far the comments aren't adding a ton of value. Hopefully that will improve.
HN has a weird doublethink when it comes to SEO/marketing. We are all "hoorah!" startups, but how dare you try to make your site more appealing to a potential customer.
Sure, there are tons of scammers that use SEO...but there are tons of scammers in every field.
No problem with that but spamming google with bought links, etc. isn't what exactly makes a site appealing to customers.