Today I retried Google's Identity Toolkit.
So I had to undust my rudimentary PHP knowledge and write some scripts and minimal html pages.
Clicking the key hole icon opens the account chooser.
I choose GMail and login to Google.
This is the result page. My site now knows some attributes about me like verifiedEmail, display name and imageUrl etc.
Next task: Repeat and rinse with http://accountchooser.net/