Until reading that article I thought this experiment was doomed to fail but it does have some potential. I hate signing up for new sites and it is cool to see friends' activities (if they choose to share them). My only concern would be sending my login information using plain text through these third party sites. It appears that Facebook uses https for login but its the strength of the weakest link that matters, and in this case if my credentials are passed via plain text to an outside site and then routed to Facebook that is no good.
Of course I have not tried it out yet so maybe they route you to a (secure) fb page to login, which is perfect.
They've had something like this for a while, and that's exactly how it works. Log-in stays secure.
I don't know if they'll make money off of this, and that's Facebook's achilles heel, but I've never understood the people who mock Facebook's features. It's the most comprehensive site I've ever used. And this is another excellent step for them.
In my opinion they are mocked because they have not introduced any groundbreaking features. They have a lot of cool features that can be found elsewhere. They are recreating what others have tried but doing it better.
Their accomplishments are execution (making a lot of features work together without crappifying the site) and scale. This is still remarkable but it does not help you avoid mocking.
I think that their privacy implementation was the first of its kind. That was the first site that I joined that didn't give me a URL. It was all about being a closed system, and I loved that and still do.
I'd also say that their ridiculous emphasis on minimalism should count as groundbreaking, because no other site gets that right, but that always leads to arguments.
I don't think you can call it groundbreaking if someone else is already doing it (I am taking the word at its most literal I guess i.e. breaking new ground).
Their privacy system is similar to MySpace's except they apply it to more things. MySpace had a system that allowed you to restrict certain things from non-friends before Facebook. Facebook's privacy system has become much more robust though.
I think the breaking ground was that Facebook's primary feature was security. MySpace had it, but they didn't emphasize it, and even when security was on, they tried to make profiles display like public pages - they just made them sparser.
Facebook introduced the completely blank page that you get when you try to go to a restricted profile. It was pretty cutting edge when I registered in 2005-06.
Of course I have not tried it out yet so maybe they route you to a (secure) fb page to login, which is perfect.