I don't think that's what a social network is necessarily - many people use Facebook entirely as a "friends only" sharing tool, and indeed almost all Facebook a

I don't think that's what a social network is necessarily - many people use Facebook entirely as a "friends only" sharing tool, and indeed almost all Facebook activity appears to be between people who know each other in real life. There are social networks that are primarily between strangers (Twitter, TikTok, etc) but that's not a defining feature of all social networks.