OpenID is a way to use your logins at one website (such as Google Accounts, Fakebook, Twitter) as an authentication service for another website (such as LinkedIn or StackOverflow). This avoids having to create separate usernames and passwords for those other sites. This is similar in many ways to CAS. Of course, you're also agreeing to new security risks with OpenID. See also CNET's article on the security flaw in OpenID.
More reading and resources:
I'll get the following working for Monday and Tuesday, so that we can play with it and learn from it:
We'll review the basic concepts and then do the following exercise:
TBD