tl;dr: Analysis of 51,000+ comments across six knife subreddits found that 5% of active accounts (49 users) produce 11.3% of brand recommendations in "what should I buy" threads, versus 7.9% expected by chance, with concentration reaching 20-31% for three specific brands. However, when the author pulled full Reddit histories of these "brand-loyal" accounts, they looked indistinguishable from regular users: 4.5 years old on average, active in 66 subreddits, and mentioning 7 different knife brands. The data can't distinguish devoted fans from well-prepared paid accounts, though the author leans toward fans.