Terminology shifted somewhere along the lines, because the nature of sites like Facebook changed. These sites were called "social networking" in the early days, since they connected people. These sites are called "social media" these days, which I assume is a reflection that the top-down nature of these sites are much more like traditional print/radio/television media.

The treatment of chat applications, online forums, etc. as social media has always felt strange to me for that reason. While the companies that offer those services may control the platform, control of interactions is limited to moderation and the content of those interactions is rarely created by a commercial interest.