Shared Sign-on

The Shared Sign-on module (previously called Single Sign-on) shares the sign-on information between multiple websites that share at least part of a database. This is different than OpenID.

In OpenID, while the same user id can be used to log in to multiple unrelated websites, they have to log in to each website separately.

With Shared Sign-on, the websites need to be related, but once the user is logged in, they are logged in to all the sites.

The Shared Sign-on module can be found (for historical reasons) at http://drupal.org/project/singlesignon