I work in a space that's orthogonal to ad retargeting, and from what I can tell after talking to people at the big data brokers, reading their white papers, and

I work in a space that's orthogonal to ad retargeting, and from what I can tell after talking to people at the big data brokers, reading their white papers, and reviewing their actual data, I've concluded that their ability to retarget is excellent but they otherwise have a really poor understanding of the targets' characteristics/demographics.