joined:Apr 1, 2016
Since 2013, we are seeing an increase in traffic, but RPM has been falling
I think there are several factors.One is ad blockers.
There is no doubt that ad-blockers negatively impact earnings in a general sense. But they are unlikely to impact RPM because, ad-blocker block the ads outright so impressions are never recorded.
Years ago, if I had a niche site focusing on a specific technology, it carried a premium RPM as this is a good topic
I Agree, and your observation about interest based ads is correct. Unfortunately the market has changed. A paradigm shift. Before advertisers would use the web-pages to target the audience using a similar approach to print advertising. But now, the web-page is of little to no importance. Advertisers target the audience (specific user) directly, and can follow the audience around as they surf. Ultimately AdSense and other networks are essentially web-page agnostic. Sure the ad must appear on a web-page, but which specific page it appears on is of little importance. As such, the competition for publishers is no longer just the other sites in your niche but any site. More supply, same demand prices fall.
To make matters worse, over the past few years the number of ad-sites has increased. Normally this would only really be a concern if the site were in direct competition with you, but given what I've described above this no onger holds, so now nearly any site is your competition.
In my experience, having a niche site continues to have value, as it remains a means of identifying individual with a specific interest. I good way to gauge interest in your site, is to check the ad-review section in AdSense, specifically the reviewed-ads, to see whether there are repeat advertisers that are consistently buying up your impressions and to see if the products being advertised are in-line with your niche.
As @Matbennett points out the ongoing privacy concerns may shift the pendulum back to assigning more importance to the website/page. In which case your position in your niche will again command higher prices. Or at least we can hope.
So what to do? I think the focus becomes, not just on number of impressions, but ensure that one a has steady user base of repeat and engaged visitors. Because there is certainly some value in getting ads from a brand in front of the same high quality and engaged users, multiple times. This is something that is not achieved with a typical MFA site.