From the FAQ:

How are stories ranked?

The basic algorithm divides points by a power of the time since a story was submitted. Comments in threads are ranked the same way.

Other factors affecting rank include user flags, anti-abuse software, software which demotes overheated discussions, account or site weighting, and moderator action.

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Personally, I appreciate that the rankings are done at a site level, and there isn’t a bunch of tracking and manipulation to give me a personal “feed” to drive engagement. A lot of comments on this site complain about those practices on other sites. I don’t think it’s welcome here.