The obvious connection to HN is that people read and upvote the popular articles, so there's (probably) a lot more randomness in what makes it to the front page than people suspect. This matches my experience, where one of my blog posts will sink without a trace on HN, and then get reposted later and shoot to the top.
Perhaps a more apt comparison would be how certain blogs (37signals, marco.org, Svbtle, etc) rocket to the front page based off of their TLD alone. I don't think this is a particularly bad thing -- this is how branding works, after all -- but I would definitely be interested to see an experiment that throws everything on Readability and hides the URL to see if things change.
I suspect there's also a "cumulative advantage" effect on comments, with popular members getting way more upvotes. Some high-karma member could quantify this by posting half their comments from a new account and A/B testing.
I could be incorrect, but I recall reading that part of the ranking algorithm is based on the commenter's average karma.