1. How this modification works. The guest would click on social networking icon such as facebook. As soon as they click on the link. The system then checks if they already signed up using that social network if not then it auto creates an account on SMF and logins in. The next time time they click on the link it sees they have an account on file on the forum and logins the user in.
The passwords are overwritten/updated each time they login. The user can not login using the normal smf login process since we are not storing a readable password and that password is not know to the user or anyone.
2. No this does not allow integration between a local wordpress blog and a forum. This mod supports logins/registration from a wordpress.com hosted platform account.
3. Works for both SMF 2.0 RC3 and 1.1.x
Demo can be found at
http://www.smfhacks.com/storedemo/