Facebook said it can't substantiate or disprove collusion.
https://www.bloomberg.com/news/arti...nsignificant-overlap-between-russia-ads-trump
But we have already established that russian ads were specifically targeted to have maximum effect.
https://www.cnn.com/2017/10/03/politics/russian-facebook-ads-michigan-wisconsin/index.html
It would be interesting to find out how they were able to target with such specificity. I wonder whose help they might have had...
It's not about substantiating collusion, just that the ads represented such a small portion of the total ads for the campaign that it was almost irrelevant.
As to how they targeted, that's easy. Facebook collects a whole bunch of demographic data that they give to any one who wants to take out an ad, as part of the fee.
At the end of the day, however, it's no different than when we (the US) use social media in other countries to get results we want.