One evening in late December last year, I received a cryptic phone call from a PR director at TikTok, the popular social media app. I’d written extensively about the company for the Financial Times, so we’d spoken before. But it was puzzling to hear from her just before the holidays, especially since I wasn’t working on anything related to the company at the time. The call lasted less than a minute. She wanted me to know, “as a courtesy,” that The New York Times had just published a story I ought to read. Confused by this unusual bespoke news alert,...