It was a few years ago, but I remember it was distinctly obvious. Stadia was new. No one really knew much about it and it was not launched yet. Several users with same-ish usernames all starting giving long well written replies that kept repeating specific talking points that were not really part of the articles or marketing, things about the product strategy that sounded very much like a social media marketing brief. And they had a lot of very nice things to say about the boss. I used to work adjacent to social media marketing and it had the fingerprint. They were either several Stadia marketing employees on a coffee break or being specifically paid for the campaign.