Once services like Friendster or MySpace gave way to services like Twitter and Instagram which rely predominantly upon the notion of the social media feed, place went away in favor of a more amorphous and identity-flattening space. Profiles as they once existed truly defined and denoted our personhood, or at least our personahood, and chat rooms and bulletin boards felt like places to visit. The feed, though, did away with all (or at least most) of that.
Add in the rise of the smartphone which was far better suited to quick-hit, bite-sized, on-the-go consumption, and out go the blogs and discussion forums and real-time chats which were so intimately tied to larger, more fixed-in-place devices.
I like this framing.
In the early days of Web 2.0 and social network, there was more of a place-ness to it. We sat down at our computer and went to a website. Whether we were aware of it or not, this separation in time and space forced a context-switch upon us.
Social media is more like two spaces laid over and among one another, forcing us to move through both simultaneously.