Just wondering if there are any live examples of this. I've found a number of sites where the FB/Twitter/Google icons appear on their create an account pages, but, none of them seem to actually work, they all go to a page with "Missing provider application credentials.".... one example: http://aircadetcentral.net/codoforum/index.php?u=/user/register

Yes, because they have not configured it.

You need to follow the documentation to setup the integration:
https://codoforum.com/documentation/setup-facebook-twitter-google-login

By "they" I assume you mean the sites I looked up, I get that.

I am looking for an example with it actually working though, so I can "sell" someone else on using this forum software, before we actually install it ourselves. Even Codologic isn't using that feature at the moment though.