If you try creating or changing an URL and you see an error message like "Someone beat you to that username," that means the username you'd like is already taken. We don’t release taken or terminated URLs/web addresses, nor can we put you in touch with the account owner(s). If you get an error message when trying to register an apparently unused URL (for example, when you see a "There's nothing here" message when you try to visit the blog), the blog may have been terminated.
If you have a registered trademark or have found a clear case of impersonation, report that to us here. You can help us with the review process by attaching a copy of your active trademark documentation and otherwise demonstrating your connection to the trademark.
Some long-unused URLs may eventually be released as part of our policy on account dormancy, which only applies to accounts that have not been logged into (not the same as "posted to") for over one year. There is no way to tell from looking at a blog whether the account has been logged into recently, but if you've got your eye on a taken URL you're welcome to wait patiently and try signing up with that URL every once in a while.