HN has traditionally been full of self-promotion, in both submitted links and especially in comments (e.g., lots of "disclosure, I made X" or "shameless plug, I made X" or ...). It's not necessarily a bad thing since the community ultimately has control over what gets seen on top. And additionally sometimes you are your only advertiser.

(In this very comments page, people are talking about their own code they wrote with links to it, etc.)