[rkuykendall-com]

Similar to Reddit or HackerNews, it depends on what communities you're in. You have to go to Twitter if you want to follow journalists, comic artists, or TV writers. I'm sure there's a lot more communities I'm not interested in where Twitter is the primary source of information, like celebrities or K-Pop.

[solarkraft]

Lots of high-profile actors are on twitter (tech influencers and politicans for 2 more examples) because it's such a direct, relatively clutter free way to get out information and have it seen.

[rkuykendall-com]

Most politicians are still only technically on Twitter, continuing the Obama-era style of very careful and boring tweets. The only three I can think of that are 100% live tweeting like humans (regardless if they're humans you like) are AOC, Ted Cruz, and of course Trump.