Anything that people spend lots of time on, and that gets to decide what they experience, is going to be influential. It shapes what they know about the world and how they feel about it, after all.
If you added up all the advertising money spent and all the payments to “influencers” and all the money spent on bot farms and fake accounts, you could approach a measure of that influence’s value.
Consider that 10% (probably more like 1%) of people make decisions that effect how society will go. At least in the English speaking world, those people care about what's happening on twitter. The other 90% use Facebook.
