Microsoft announced in May, to the delight and relief of many, that a Start button would be added to the desktop UI of Windows 8.1 when it is released later this year. However, in Microsoft's official screenshots and video showcasing Windows 8.1, the Start button isn't actually displayed.
However, Microsoft finally decided to give the audience at its Computex 2013 keynote address in Taiwan a quick glimpse of the Start button in action this week. Networkworld.com posted the video on YouTube, which features the Start button around the 1.16 mark.
The video showcases another feature of Windows 8.1 that lets users set up the background of the desktop so it can be the same as the background for the Modern style Start menu. The video shows that clicking on the Start button on the desktop screen brings up the Start menu, but since the background is the same for both, there's no sense that there's been a huge jump from one UI to another.
The video also shows the new All Apps part of Windows 8.1, which will allow users to view a list of Windows 8 apps with small icons on screen as an option to the regular tile-based Start menu.