Thanks Dave - I didn't know the function of a DMP (or the acronym), so that's an interesting thing to learn about. Sounds like there are some real-time data auction houses for advert targeting as well, which is interesting.

I expect the volumes and retention of this kind of data are fairly unregulated at the moment? I certainly haven't heard anything consistent as a consumer about how this data is collected/used (also bearing in mind international considerations in many cases)