A lot of online comments are just people repeating what everyone else is saying.
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From the Jin-dynasty poet Cai Songnian's《槽声同彦高赋》: 他日人云吾亦云 — 'in days to come, if others say it, I'll say it too.' Originally self-deprecating, now used to criticize others.
memory
Two 云 (yún, classical for 'to say') flank 亦 ('also'): 'people say, also say.' The character pattern itself echoes the parroting behavior.
