We understand that site owners may want to monitor the type of ads being shown on their site. However, it is important to remember that ad targeting is not an exact science and every user sees different ads, many of which will be retargeted based on the user’s previous browsing behavior.
Website owners for example often cycle through many more ads than would be ever seen in a normal visitor session, which will result in a slightly poorer quality of ad being presented to them.
Why is this?
It's generally accepted that the first pageview of any user session is the most valuable. The reduction in quality/usefulness to an advertisers goes down thereafter due to lack of attention to the ads. So when someone views a large number of pages from a single IP / cookie, particularly within a single user session (remember that on most sites the average visitor will view a few pages of content and this varies by site), the quality of the fill rate and / or the ad quality will go down (because the site owner will be absorbing many more than the average number of pages).
What can I do?
If you're concerned about either the ad fill rate or the quality of the ads being shown on your site, it's worth viewing your site from a different browser or better yet, device (that you haven't previously viewed the site from). You could also use a VPN to browse the site from another location besides your own. If you notice an improvement with regards to the ad fill rate or the quality of the ads being shown on your site, this strongly suggests that everything is working as expected, and that the only reason you are encountering a lower fill rate or poorer quality of ad during your usual user session is that advertisers aren't willing to pay as much for your attention as they are a first-time visitor.
If you witness little improvement during this experiment, this usually indicates that advertisers simply aren't willing to spend as much targeting your site's audience as they are others. This typically goes hand in hand with low-paying audience locations, low EPMVs etc. If this is the case (and revenue is a strong concern for you), you may wish to think about how you can attract visitors to your site that advertisers will be willing to pay more for.