More and more people are concern with privacy and start deleting cookie to prevent being tracked. How will this impact on the ad network?

1. Undercount the conversion (both click and view-based). However, vast majority of conversions (70-90%) occur within 24-hour window of the corresponding click or impression and there are not too many people delete cookie daily. So, the impact is not that much.
2. Underestimate the frequency and overestimate the reach
3. Users may continually fall off the profiled segment and behaviorial targeting. If the trend continues, that may translate to less available profile inventory, which could result in higher prices or under-delivery. Nonetheless, cookie deletion should not diminish the value of the targeted impressions that publishers are currently able to deliver. There are even an argument that cookie deleting may actually increase the value of targeted inventory since recency is a dominant driver of effectiveness in behavioral targeting.