Google have released the latest addition to their growing crop of online services. The latest entry is targeted at web developers who want a simple solution to user authentication. Similar to Microsoft's previous offering of Passport (later scaled down to Microsoft only sites, and soon to be re-branded in the Windows Live group of products) it allows users to register once, for a Google account, and use that single login to access any site which supports that system.
All the authentication is handled by Google's own servers, and the website can only access information about the user that the user themselves chooses to share with the site. This prevents malicious websites from stealing private information about the users.
By default, applications using this service are not trusted — and so when a user attempts to log in, they are given a warning message. By registering, websites will be recognized as "trusted" by Google and therefore will not display the warning. Soon Google will also release a way for registered websites to display their logo on the page as well.