This may not directly relate to monopolistic behaviour - but I remember once (pretty recently) when Jack/someone in his team revealed a screenshot of an interface in their backend that literally allows them to control public mood and opinion- such as trends, shadow banning, etc. To me, that is scarier than just being a monopoly. Imagine, you pull the right switches during an election campaign that could sway public opinions in the last minute (regardless of the political party you support). How they aren't under serious scrutiny after releasing such interfaces to the public is a grave concern to me.