I'm wondering if a plugin exists that will show a form only to users that have first authenticated via Google, Twitter, Facebook etc. Hopefully it would be as simple as wrapping some content in a shortcode. If the user isn't logged in, it shows the login buttons for those services, if they are they see whatever content (in my case a form) is between the shortcode. Has anyone seen a plugin like this? If not I might look at developing something like this.