LiveID is a single sign-on service provided and maintained by Microsoft. By integrating LiveID into your web site, you can allow site visitors to log in to your web site using their LiveID login and password. Even unregistered users can log in using their LiveID, in which case a new user account will be created automatically based on their LiveID account.
The following diagram shows how the process of LiveID login works.
For this to work on your site, you have to do the following things:
1. Register your web site at https://msm.live.com/app - to learn how to do it click here
2. Set up Kentico CMS LiveID support - to learn how to do it click here
3. Add the LiveID web part to your site and optionally add and configure the Live ID required data web part - info here