Ask HN: Interesting topics to research around online advertisement?

I am soon writing a Master's thesis, and I am looking for ideas for interesting research avenues in the area of online advertising.

Currently, some of the research questions I am considering are: - What is the future of Open Web and will it be ad-supported? - How to reconcile privacy and data monetization in online space? - What social implications could the decline of open web (e.g. independent news media) have? (decline due to e.g. AI)

I have access to a lot of anonymous traffic data of some european news sites; also contacts in the industry.

What is a problem in this space you wish someone dived deeper into?