Developers of applications that require end-user authenticated interaction
with Google services now have several options for authenticating:
Installed
Applications: "The ClientLogin API lets you incorporate
programmatic login into your desktop or mobile applications. This API incorporates CAPTCHA for
greater security against password trollers."
Proxy for Web
Applications: "The AuthSub API gives your web application
the ability to access a user's Google services accounts without handling the user's login
information. This API offers a secure mode, in which the web application can register with
Google for greater security."
