Traditionally, users who log in to a website must use a separate account for each site. OpenID allows a user to create a single account that is used at every website that accepts OpenID logins.

with a spanner

OpenID allows you to access multiple sites with a single sign-on. This means that you don't have to remember unique usernames and passwords for each site that you use.

An OpenID is used to control the amount of information that is released to every website you access (such as your name and email address). With OpenID, your password is given only to the identity provider and that provider will help confirm your identity to the websites you visit. Other than your provider, no one will see your password which will stop websites from figuring out your identity.

using Zend OpenID Consumer