Looks like now Google is becoming serious about Single Sign On process of OpenID following Yahoo! (although not exactly, Blogger added OpenID based comment support feature long back in November ’07). Blogger has announced the support for OpenID 1.1 in Blogger Draft.
You can register your Blogger blog as your website URL to get the authentication but presently it is limited to Blogger domain only and can’t be extended to hosted blogs like FTP etc. There is a work-around, however, as mentioned by Blogger on the post –
We currently do not support OpenID for blogs that aren’t hosted on Blog*Spot or a custom domain, such as FTP blogs. However, the OpenID web site has a help page that explains how to workaround this limitation by delegating your FTP blog to a Blogger-hosted blog.
So still a long way to go for Blogger to help users experience true OpenID implementation…