Windows Live authentication, is in many ways similar to OpenID, in that it allows users to register or sign in to your site without having to create yet another new password. Its definitely worth enabling Windows Live if you are enabling OpenID because there are already millions of people who have a Windows Live account. Anyone with a hotmail or MSN account has a Windows Live ID because these things have all been integrated by Microsoft.
When you create your Windows Live Application ID on the Microsoft site, you will be asked to provide a return url. You should enter http://yoursiteroot/Secure/WindowsLiveAuthHandler.aspx or if you have an SSL certificate then use https://yoursiteroot/Secure/WindowsLiveAuthHandler.aspx
To use Windows Live Authentication in mojoPortal content management system, you have to get a free application id from Microsoft and enter it in (key icon) Administration Menu > Site Settings > Security > Windows Live
It is possible to disable Windows Live from Web.config or user.config with this setting if for some strange reason you want to disable it. If you disable it there, the Windows Live Tab will not be displayed in Ste Settings.
<add key="EnableWindowsLiveAuthentication" value="false" />
I recommend you keep it enabled, it still won't work unless an application id and key are entered.