The official Google blog has a post announcing the changes made by Google to the preferred domain feature of the webmaster tools. When Google initially launched the preferred domain feature , it added the non-preferred version to the users account, so that he could see any information associated with the non-preferred version. This was confusing, so now certain changes have been introduced. Now, on setting the preferred domain, the non-preferred version will no longer be added to the your account. If the non-preferred version has alreday been added to your account, then it would be removed over next few days. And, in case you would like to see any information about the non-preferred version then you can always add it to your account. The FAQ has been updated with tons of new questions and replies about the preferred domain feature.