I have now added this as an idea in the Community Voice area:  http://www.dotnetnuke.com/Community/Community-Voice/suggestionid/102.aspx

If you've read this far and agree with my opinions then please go and vote there....

IMHO - if you really want facebook and other social site integration features - DONT use whats built in  -  its just not ready for prime time.

We wound up building our own facebook login and rego integration from a client and the could not be happier - it does exactly what they want - which is let people associate their Facebook and DNN accounts - be they new or existing.

Westa 

Keep in mind that 3rd party DNN Modules found in the store already tackle very well social login and integration... iWebs (Interactive Webs) has Advanced Login which does a great job at allowing for Twitter authentication, Facebook authentication, google authentication linked in authentication, yahoo authentication and zendesk authentication.

With all of those options and abilities to login by username or email (or both) and then confirm by password or lastname or zip code or custom profile field, etc, the topic of options for login has been well covered by this and other modules (DataSprings Dynamic Login comes to mind). So plenty of options to do odd and custom things, or use the core for straight-forward solid login through the main provider and other authentication methods like Live, AD etc