Single Sign On using PURL domain modifier and different TLDs I have an organic groups implementation using purl and spaces to set the active space when you visit a domain modifier such as example1.org vs example2.org.  The cookie domains are different, so I'm wondering if there is any single sign on solution that will allow sessions to be transfered from one domain to another in some fashion.  

Should I use something like facebook connect, and not allow users to sign onto the site with their regular drupal credentials?
Have also been looking into this the last few days and came across this

http://drupal.org/project/services_sso_client

Seems that it will do exactly what you want to do.