Nearly two decades ago, Facebook exploded on college campuses as a site for students to stay in touch. Then came Twitter, where people posted about what they had for breakfast, and Instagram, where friends shared photos to keep up with one another.
Today, Instagram and Facebook feeds are full of ads and sponsored posts. TikTok and Snapchat are stuffed with videos from influencers promoting dish soaps and dating apps. And soon, Twitter posts that gain the most visibility will come mostly from subscribers who pay for the exposure and other perks.