The User API is an API extension that has been added on the release date of the new developers platform. Its use is to give foreign parties, e.g. clans on TrackBase, an interface where they can gather information which are stored on TrackBase. With this API the developers can use private user information from TrackBase. So, as an example, developer XYZ could require the username and email address and let the user create an account on his / her own website with TB information.