Love it or hate it, it's the new self-promotion/branding via blogging. If a controversial article makes it to the top of a popular or niche internet forum like HN, and you have something of substance to say about it, it's infinitely better to post your thoughts on your own blog instead of in the comments of the social news submission.
The niche forum sees it, and you can claim credit in the comments, associating your handle with your blog. But more people may see it - potential clients, employees, funders, cofounders, employees, etc - and it's good way of beating writer's block and adding content to your professional blog.
I've seen questions about how to do something in linux/windows downvoted (replying to people who suggested homebrew or macports)
The one complaint that I definitely have about the HN quo is how it feels like conversations are trying to be transposed onto the medium; someone posts a PHP/Apple/Olympics rant and then half the top links are swallowed by thinly veiled 'responses'. It seems like the wrong approach, splitting multiple conversations on the some topic.