Digital publishers increasingly use advertising as a monetization strategy. At the core of ad-based monetization is behavioral ad targeting, which creates a sustainable revenue stream for publishers and keeps online content mostly free. However, behavioral ad targeting requires the collection and use of consumer-level data, which leads to privacy concerns among consumers. Although the main intent of privacy regulations is to safeguard consumer privacy, a consistent finding from past empirical research is that privacy regulation hurts digital publishers. Specifically, prior research suggests that the revenue loss due to privacy regulations is more pronounced for general interest (vs. specialized) publishers, who have greater uncertainty about their consumer types without consumer tracking. For example, in the absence of consumer tracking, a mainstream news website such as the New York Times - which attracts a highly heterogeneous pool of readers - has a harder time inferring consumer types and interests in order to show them relevant ads, compared to a niche, ideologically extreme website such as Infowars.

The Internet has had a significant impact on how consumers discover and evaluate products, particularly by means of consumer reviews. Learning from reviews, however, is made difficult by the fact that, to some extent, reviews measure idiosyncratic consumer-product fit, and not just objective quality. In this context, how and what can consumers learn?

We study the impact of consumer quality-based self-selection on online reviews. Consumers differ in their expertise, which has two effects. First, expertise is instrumental to choice: Experts purchase better products than Non-Experts. Second, because of their superior choices, Experts endogenously form higher reference points, which leads them to post harsher ratings for a given quality. Combined, these two facts imply a bias against higher-quality products. When this bias gets large, ratings are non-monotonic in quality: lower-quality products can obtain higher ratings than superior alternatives, thanks to the lower standard they are held to.