For starters, they accessed 4X the number of profiles that CA did. I have edited my comment, however, because it appears that they did (just like CA) have an a

For starters, they accessed 4X the number of profiles that CA did. I have edited my comment, however, because it appears that they did (just like CA) have an app that they used. Except they used it, as one Obama campaign manager put it, to "suck out the whole social graph" of voters in the US, and Facebook "was surprised, but didn't stop [them] once they realized they were doing it". By the way, this is something that would have been stopped on any other app long before they ever accessed 190 million profiles. So Facebook essentially gave them the entire US social graph, that they wouldn't have allowed any other app with only 1 million users to have.