When setting up the new build of Windows Live Messenger, you may have noticed a new option for installing Windows Live Sign-in Assistant. This new service allows you to quickly switch between your Live ID accoounts when using multiple Live ID's. Its an Internet Explorer Add-on that helps save your accounts. Program Managers for Windows Live ID Mark Wong and Erren Lester
discuss Windows Live Sign-in Assistant in great detail on their blog.
Multiple Windows Live ID accounts are often used on a particular computer, either because multiple people share a computer (like in a family home), or, because you are an individual user with multiple accounts (for example, separate accounts for ‘work’ and ‘home’). A key feature that Windows Live ID sign-in experience will offer is the ability for our users to save multiple credentials on their machine. These multiple accounts will be shown as a list on the sign-in page – you’re even able to save your password for each of these accounts, eliminating the need to re-type your password everytime you want to change your identity!
You can test drive the new Windows Live ID and Sign-in Assistant by signing it at ideas.live.com. Expect more websites to begin using Windows Live ID as the rollout continues!