One view of this is HN sports two ranking algorithms: the front page and /active. A few months after discovering /active, I found I was not looking at the front page. I've come to the conclusion it's gamed (not by HN of course, but the various tribes flighting for attention), and yes the primary mechanism for that is flagging.

Having two ranking algorithms is very bluesky'ish in some ways, and thank $DIETY it does. The front page reminds me of other sites that have voting systems. I don't know how to describe it - but I get the sense they all tend to favour articles the tribes like fighting about. /active has much less of that feel.

The comments on HN also suffer from the same tribal warfare effect - with the comments the tribes like fighting over rising to the top. That isn't so bad - because it means you can often just skip the top couple of comments to go fossicking for the insightful gems.