Hold on there. We added RPX (wraps Google, FB, Twitter, etc, etc) signup/login in addition to our username/password and the response has been...unexpected. We still have well over 50% of people sign up with username/password instead of RPX. I had expected a huge shift, but it didn't happen.

Sure, maybe some of those would have used RPX if that were the only thing we had, but apparently they still prefer a username.

Going 100% with the 3rd party logins is a tricky route. It's impossible to know how many potential signups you're losing.