In a nutshell, OpenID lets you create one username and password you can use on thousands of Web sites, simplifying your online experience. There are a lot of big names involved, including Yahoo!, AOL, Facebook, PayPal, Google and Microsoft; however, not all of these companies let you use an OpenID yet to login into their Web sites.
Today it is estimated that there are over 160-million OpenID enabled user names/passwords and nearly ten thousand sites supporting OpenID logins. You may even have one already, if you have an AOL screenname or a Yahoo! login, for example. To find out more about where OpenID can be used and how to get one, visit the OpenID official Web site below.
If you are going to trust everything to one username/password, you need to be really sure it is safe. With OpenID, your security depends on where you first sign up for it. When you login, other Web sites will go back to your original OpenID registration site to check your username/password. Try to find a registration site that offers the option of a personal security device for your online safety, such as Yahoo! for example.
Another option to consider is to use an OpenID or InfoCard provider who offer a stronger authentication process such as a secure USB token rather than password recognition.