You may not use the terms "Facebook" or "Face" as any part of the name of your Facebook Platform Application, including without limitation "Facebook [application name]", "[application name] on Facebook," "[application name] for Facebook," or "Face[application name]." Further, you may not use the term "Facebook", or variations or misspellings of Facebook (e.g. FBOOK), in the name of a URL to the left of the top-level domain name (e.g., ".com", ".net", ".uk", etc.) -- for example, URLs such as "facebook.xxx.com", "faacebook.com ", or "facebookprofiles.net" are expressly prohibited. Other than your limited right to use the Marks in a non-trademark manner as provided in this Agreement, you may not make any use of the Marks. Facebook and its licensors retain all right, title and interest in and to the Marks, and all goodwill arising out of any use of the Marks by you will inure to the sole benefit of Facebook. You will not at any time now or in the future challenge or assist others to challenge the validity of the Marks, or attempt to register confusingly similar trademarks, trade names, service marks or logos. You agree to follow any Trademark Guidelines established by Facebook with respect to your use of any Marks as those guidelines may change from time to time. You must immediately discontinue use of any Mark as specified by us at any time in writing. We may modify any Marks provided to you at any time, and upon notice, you will use only the modified Marks and not the old Marks.