What is OpenID?
OpenID is a shared identity service, which allows Internet users to log on to many different web sites using a single digital identity, eliminating the need for a different user name and password for each site. OpenID is a decentralized, free and open standard that lets users control the amount of personal information they provide. OpenID eliminates the need for multiple usernames across different websites, simplifying your online experience.
You get to choose the OpenID Provider that best meets your needs and most importantly that you trust. At the same time, your OpenID can stay with you, no matter which Provider you move to. And best of all, the OpenID technology is not proprietary and is completely free.
Where can I use my OpenID?
You can use your OpenID on any one of a growing number of sites (nearly ten-thousand) which support OpenID. If one of your favorite sites doesn’t support OpenID yet, ask them when they will!
How do I get an OpenID?
There are several ways to get your OpenID such as AOL, Blogger, Flickr, LiveDoor, LiveJournal, Orange (France Telecom), SmugMug, Technorati, Vox, Yahoo, and WordPress
.com.
Source: OpenID