Hacker News Reader

I'd hypothesize many large firms track relevant subreddits

Some tabloids blatantly lift articles from Reddit. One such subreddit decided it was enough and regularly take them to task over it.

A note of caution, the link contains British humour and liberal use of sweary words.

/r/nba has also proven plagiarism in the past

I have a hunch Costco purchasers view reddit for product reviews and ideas.