Threads, the new “Twitter killer” app rolled out by Meta CEO Mark Zuckerberg, has surpassed 100 million users in less than a week while Elon Musk’s micro-blogging site has seen traffic “tanking,” according to a tech executive. The initial burst of success for Threads has fueled a war of words between Musk and Zuckerberg. The Twitter boss referred to his tech rival as a “cuck” and challenged him to a “d–k measuring contest” over the weekend. Not only have users been signing up to Threads through their Instagram accounts, but they have also been posting prolifically. Since the system went...