Our policy says: Usernames of well-known living or recently deceased people, such as Nelson Mandela, Céline Dion, Noam Chomsky, and Stanislaw Lem, unless you are that living person. If you are, please note this on your user page. These accounts may be temporarily blocked pending confirmation, if in an administrator's best judgment there may be doubt over the validity of the claim. (from Wikiquote:Username).
This account falls upon on this category in my opinion. I guess the admin who placed blocking on this account may have the same idea. Avoiding the confusion, the restriction is applied on the people who have eventually the same name of celebrities.
If you are however Ms. Britney Spears, the famous actress herself, you are invited to contact us by email. Otherwise, the blocking placed on this account won't be lifted.
Thank you for your understandings, --Aphaia 13:54, 31 October 2007 (UTC)
The developer team at Wikimedia is making some changes to how accounts work, as part of our on-going efforts to provide new and better tools for our users like cross-wiki notifications. These changes will mean you have the same account name everywhere. This will let us give you new features that will help you edit and discuss better, and allow more flexible user permissions for tools. One of the side-effects of this is that user accounts will now have to be unique across all 900 Wikimedia wikis. See the announcement for more information.
Unfortunately, your account clashes with another account also called Britney Spears. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Britney Spears~enwikiquote that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name.
Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.