You can quibble about definitions, but I'd say it's got a lot to do with being personalized. So anything where you need to know something about the viewer in order to optimise what to show each individual. That can be for anything from the content itself to the advertisements, if you need to know something about who is watching, it's what we currently think of as social media.
FB, Instagram, TikTok, but also Google search, and every ad supported site.
FB, Instagram, TikTok, but also Google search, and every ad supported site.
Not WhatsApp or the chat services, interestingly.