How do StackExchange sites associate user accounts and OpenID logins?

Question

I love StackExhchange / StackOverflow\'s approach to integrating OpenID.

As I understand it, the process goes something like this:

• If a user signs up with

Answer 1

The StackExchange sites use the DotNetOpenAuth library (previously known as DotNetOpenId library).

You basically need a User table and a User_OpenID table with a one-to-many relationship. Scot Hanselman has a good basic article or try a more in depth overview