Microsoft's smartphone business is in free fall, with the company selling just 2.3 million devices in the last three months. It's likely that you'll still be able to buy a Microsoft-branded smartphone, but it's probably not something the firm will devote a lot of time and energy to. After all, making phones is an expensive business, and if there's no chance to make any sort of profit, it's not worth the effort. If you've been watching Microsoft over the last five years, it'll come as no surprise that its smartphone plans have foundered. If you want to explore the evolution and collapse of Microsoft's mobile ambitions, check out our timeline.