Elon Musk is finally buying Twitter, promising – or to some, threatening – sweeping changes for one of the world's biggest social media platforms. With a self-proclaimed remit to ensure everyone's timeline becomes the ultimate home of free speech, and a vague long-term goal to transform it into "X, the everything app", the billionaire is taking a hands-on approach. Sky News takes a look at what it might mean for the future of the platform, and whether users should be hopeful or concerned about what is to come. The first step to 'the everything app' Musk has spoken repeatedly about…