If you register for an account with Foursquare, you shall provide Foursquare with accurate and complete registration information (including, but not limited to your email address and/or mobile telephone number (optional) and a password you will use to access the Service). Failure to do so shall constitute a breach of these Terms of Use, which may result in immediate termination of your Foursquare account.  We recommend, but do not require, that you use your own name as your user name (“User Name”) so your friends can recognize you more easily. We recommend, but do not require, that you use your own name as your user name (“User Name”) so your friends can recognize you more easily. We recommend, but do not require, that you use your own name as your user name (“User Name”) so your friends can recognize you more easily. Foursquare reserves the right to refuse registration of, or cancel a user name, in its sole discretion.  You are solely responsible and liable for activity that occurs on your account and shall be responsible for maintaining the confidentiality of your Foursquare password. You must be at least 13 years of age to access of use the Services. If you are under 18 years of age (or the age of legal majority where you reside), you may only access or use the Services under the supervision of a parent of legal guardian who agrees to be bound by these Terms of Use. Foursquare cannot guarantee the authenticity of any Content or data which users may provide about themselves. You acknowledge that all Content accessed by you using the Service is at your own risk and you will be solely responsible and liable for any damage or loss to you or any other party resulting therefrom. THE SITE, SERVICE, CONTENT AND SAVE-TO-LINK ARE PROVIDED "AS IS", "AS AVAILABLE" You shall defend, indemnify, and hold harmless Foursquare, its subsidiaries, affiliates and each of its and its subsidiaries’, affiliates' employees, contractors, directors, suppliers and representatives from all losses, costs, actions, claims, damages, expenses (including legal costs) or liabilities, that arise from or relate to your use or misuse of, or access to, our Sites, Services, Content, Save-to Link or otherwise from your User Submissions, violation of these Terms of Use, or infringement by you, or any third party using your account, of any intellectual property or other right of any person or entity 

Summary:
You must provide your identifiable information. The service can suspend your account for several reasons.  Pseudonyms are allowed. The service allows you to use pseudonyms. The service allows you to use pseudonyms. Usernames can be rejected or changed for any reason. You are responsible for maintaining the security of your account and for the activities on your account. This service is only available to users over a certain age. Minors must have the authorization of their legal guardians to use the service. The service does not guarantee accuracy or reliability of the information provided. The service is provided 'as is' and to be used at the users' sole risk. The service is provided 'as is' and to be used at the users' sole risk. You agree to defend, indemnify, and hold the service harmless in case of a claim related to your use of the service.