Comment by npteljes

Same as every social platform, the network effect. The actual functionality really is secondary to the usage and culture of these. Very much affecting it, yes, but still secondary at the same time. Same with multiplayer games, hangout spots or third places, and the list goes on.

There are many circles where xitter is a default platform. For example, many anime-style nsfw artists publish there as a primary outlet, and many companies publish their most instant news there (like a service outage, change in the opening hours, things like that). That and many other such things are plenty to keep people there.