The literal cause of the error "Another blog or Google Site is already using this address." is that the Google Sites service is mapped to the address in question, in the Google domain services mapping database. Some help articles published on the Internet imply that Sites mappings are the only cause of this error. This misconception creates some of the confusion associated with the error. Sites is not the only service in the services mapping database - but it is the only service with web address mappings. The Sites service contains both service address, and web address, mappings - and both mappings can cause this problem. This oddity creates complexity, and makes a linear check list impossible, when using Google Apps to clear the error - as well as diagnosing the error, in a typical dialogue in Blogger Help Forum: Something Is Broken .