Blogger announced that OpenID commenting is now available for all Blogger blogs. OpenID eliminates the need for multiple usernames across different websites. You can disable anonymous commenting in Blogger and get rid of any comment spoofing. Most of your readers would have at least signed up at one of the services supporting OpenID.
How it works? Your blog readers can now leave authenticated comments on te blogs using their blog URLs from OpenID-enabled services such as WordPress.com, LiveJournal, AOL Journals, or AOL/AIM accounts. Comments left of your blog by those signing in with their OpenID URL will display a small OpenID icon next to their name. The icon links back to that person’s URL so you can verify their identity.
If you use AOL, Technorati, WordPress.com or LiveJournal, you already have your own OpenID. OpenID is just announced recently. So more and more providers and signing up and enabling their site for OpenID.
You can log in with your username (the OpenID URL) and password at one site and you only have to enter your username (no password) to access other sites. This is called single set of credentials sign on. Remember, OpenID is not SSO (Single Sign On). Using SSO, you can log with your username and password at one site and access other sites without logging in again during a session.