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?
Google calls it 2 step verification. They do not ask for it every time you log in. Only when you log in from a new computer, if you have not used the code in a while, if they think there is something suspicious with your account usage, or, if you clear your cookies from your browser so it appears to be a login from a new PC.
They use this system so that it is not such a big pain in the neck for newbies to 2 factor auth. This is to help convince people to add the 2nd factor.
The theory is that many users are hesitant to use 2-factor because it is an extra step they need to take. If they only need to do it once in a while, but it ensures that someone in China trying to hack the account has that extra hoop to jump through, they are more likely to use it.
Yes, it works on Google. Most likely what happened, IMHO, is it didn't ask because you were on the same computer that you set it up with.
I see you've asked another question about non-Google services, so I won't answer that here.
