The Mastodon site is shown on a smart phone in Oakland, Calif., on Nov. 11, 2022. Sites like Mastodon and even Tumblr are emerging as new (or renewed) alternatives to Twitter.Barbara Ortutay/The Associated Press Twitter has been a bit of a mess since billionaire Tesla CEO Elon Musk took the helm, cutting the company’s work force in half, upending the platform’s verification system, sparring with users over jokes and acknowledging that “ dumb things ” might happen as he reshapes one of the world’s most high-profile information ecosystems. On Thursday, amid an exodus of senior executives responsible for data privacy,...