Twitter, despite feeling ubiquitous to people in the media, remains a relatively small platform.
This chart from BI Intelligence shows that just 18% of U.S. Internet users are on Twitter. The people that are on Twitter are using it largely to track news.
There’s two ways to look at this. On the one hand, it means Twitter has room to grow. On the other, it suggests Twitter isn’t mainstream, and it might not ever go mainstream.