I wonder if this will track parts of the OpenID movement? Many have registering more than once and everyone doesn't want to have to type too much stuff in to get what they need, while advertisers want to know more about you. OpenID doesn't provide that just yet, but perhaps it will.
This begs the question if all of these social networks share the same information why use one over the other?
social web is far beyond one platform or the next, fb may be winning vs. myspace, but they are leaps and bounds from nearing google.
this is big news for startups - there are a lot of great bits to use from this.