HN aggregates, it has no illusions of creating original works. Occasional high-quality reposts are a virtue of HN, and I don't think HN suffers from the same regurgitation issues as film sites. The film websites often come with analysis or reviews of films where the regurgitation lies, whereas Hacker News provides no editorialized comment on the articles, only discussion.

"Echo Chambers" etc... could be merely a distributed version regurgitated content, however I think the HN community tends to self-police groupthink