Just because a bunch of forums do it that way doesn't mean it's correct. When I was at Twitter the Compliance team determined that all user-generated content was Personal Data under the scope of GDPR. Those forums may be getting away with it right now, but they're playing with fire. If someone wanted to raise a stink with regulators they could be in trouble. I guarantee you if Reddit or a site of similar scope tried something like that someone would.

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