Google wants to save users the trouble of remembering multiple usernames and passwords by letting other websites use its login system, the Identity 2.0 blog reports. For websites, the motivation is two-fold: They won't have to spend time coding their own login system, and they can tap into Google's growing user base. For users, the appeal seems simple -- they won't have to remember yet another username and password. (Only Google will see the user's password; the website will just get an "authentication token" meant to prove the user's identity.)

But Google's new Account Authentication system poses some troubling issues -- largely the same ones Microsoft faced five years ago when it tried to introduce Passport, a similar master password for the Internet. The debate back then was fierce, but boiled down to this question: Can we trust a single company with all of our online identities?

Digital ID World notes an irony here: Microsoft, bruised by its past experience, is relaunching Passport as Live ID, which lets websites use any online ID directory, not just the one Microsoft currently uses to let people log into Hotmail and other MSN websites. Google's system, by contrast, only works with Google usernames and passwords. And of course, it makes Google the sole guardian of our digital identities. So: Are you ready to hand over your ID?