OpenID is a single sign-on system that lets you use the same username/password across multiple sites. OpenID is available through multiple providers (AOL, LiveDoor, LiveJournal, Technorati, WordPress, Blogger, and soon, Yahoo) so chances are, you already have an OpenID.
Your OpenID is in the form of a URL that includes your screen name such as openid.aol.com/screenname, username.livejournal.com, or username.wordpress.com. By entering this URL into the form above, you can simplify the PropertyMaps registration process and determine what amount of information you want to provide. Plus, we won’t require email confirmation for account validation.
For more information, take a look at the OpenID website.