What's the new Single Sign-On in the admin portal?

[Geoff_Krajeski1]

Has anyone else seen this?

Could I use it to unify the login experience for my website users across my many websites?

[SanfordWhiteman]

SSO is for Marketo logins, not logins to your web properties.

EDIT: if by "my many websites" you mean Salesforce, Marketo, and other app providers, then yes.  The idea is to help consolidate the number of usernames/passwords/certs a user needs to manage.