What is the difference between a self-created certificate, a Symbian developer certificate, and Symbian Signed?

Because signing is mandatory in S60 3rd Edition, all applications must be signed with a certificate to be able to install the application to a device. If the application doesn’t need any capabilities, it can be signed with a self-created certificate, which can be created with the S60 3rd Edition SDK. If capabilities are needed, a Symbian developer certificate is required in the testing and development phase to be able to test the application on a real device. For final applications, some capabilities are granted only through Symbian Signed, so the application must be Symbian Signed to gain access to certain capabilities. Also, Symbian Signed may be a requirement for getting the application to a manufacturer or operator sales channels, for example.