If you plan on publishing your project, you will likely need a developer account. Many of these require that you have a mail account associated with their authentication method. Here’s a few pointers on where I’ve gone to sign-up.
Android Developer – Google Play (https://play.google.com/apps/publish/)
Windows Development – Windows Store (https://appdev.microsoft.com/StorePortals/en-us/Home/Index)
Windows Azure – Cloud Computing / Storage (http://azure.microsoft.com/en-us/)
Network Solutions – Domain Registration (http://networksolutions.com)
YouTube – Videos, Demonstrations and Tutorials (http://www.youtube.com/yt/creators/)
WordPress – Blogs (http://wordpress.com)
You may know of others. This is the list of ones I’ve recently frequented.