Meta’s Threads is on a roll. The social networking app is now home to more than 400 million monthly active users, Meta shared with Fast Company on Tuesday. That’s 50 million more than just a few months ago, and a long way from the 175 million it had around its first birthday last summer.Launched in July 2023 with a record-breaking 100 million signups in its first days, Threads quickly positioned itself as Meta’s best shot at challenging Elon Musk’s X. Mark Zuckerberg, Meta’s CEO, made no secret ...