I set up Google 2 Factor auth to use 2 Factor Auth with certain sites. But reading over the help suggests that Google 2 Factor Auth is only used to log into Google services like Gmail.
But when I log into Gmail, to does not ask for 2 Factor Auth code.
Is Google 2 Factor Auth used to log into Google services?
Where is the documentation for using Google 2 Factor Auth to log into non-Google services?