Linking your online ID will let you log in to Windows and then log in to any service for which you’ve installed a provider, without being prompted to login again. I associated my Windows Live ID with my home desktop computer login. When I went to Hotmail, all I had to do was click my email address to log in. I went over to MSDN to check my available downloads and simply clicked “Sign in” and was there. Pretty cool feature and a great time saver.

Here’s how to do it:

Click the Windows button.
Type “link online” and you should see “Link Online IDs” at the top of the search. Click it.
Select “Add an Online ID Provider” and select one from the list – at the time I’m writing this, only MS Live is available.

Download the installer, and install. You should see this:

Click “Link online ID” and enter your credentials. That’s it! Now head over to your Live/Passport enabled sites and login!