An interesting new features lets you link a main Windows Live account with other secondary accounts and use a single login to access all your accounts. At the top of the page, next to your email address, there's an arrow that hides a list of your linked accounts.
Windows Live IDs are the key that unlocks many web applications from Microsoft and you can get one when you install the Windows Live suite, a Google Pack without third-party software. As we could see in the previous article about Windows Live, Microsoft's strategy is to deliver a unified package that combines its best software with its online extensions. Microsoft pitches it as a Windows upgrade and a simple link from Vista or from Windows Update is enough to capture a big audience. "With Windows Live, you'll get software and services that make what you can do on your PC and the Web just that much more amazing. Think of it as the power of Windows combined with the limitless possibility of the Internet." (my emphasis) That's probably the reason why some web apps from Microsoft work better in Internet Explorer: they're not supposed to work optimally on any platform and any browser, their purpose is to enhance the default Windows experience.