Did you read the article? They paid several hundred thousand people via Mechanical Türk to download their poll app and then harvested 50M users data for political targeting.
Data they could have acquired directly from FB anyway? It seems like they found a way to make the data acquisition process more efficient (while also violating FB's TOS, which is the actual problem here).
But the point is, the methods CA used to influence voters weren't significantly different from Obama's 2012 campaign.
There is a giant difference here in the fact that the data acquired for CA was through a third party. Data obtained through the Obama campaign was through the Obama app.
