You might have previously blocked them in a different way. As things evolve, settings that may have seemed good at the time need a look. ;)

I tried to think of ANY situation where that might have happened, but there's just no way that I could have blocked 2,350 sites and forgotten! LOL That would have required blocking 6-7 sites every day for a year! I would have blocked ads for ad blockers and Facebook, but that would be about it.

The very first site on the list of 2,350 is the (long defunct) 007zip.com. I looked it up on the Wayback Machine, it seems to have disappeared in 2018, and from 2014-18 it was selling some type of ad network:

[web.archive.org...]

I can't think of any reason that I would have blocked that.

And the fact that it's a very even number makes it seem automated.

The only other thing I can think of is that I did use their Ad Balancer when it was a thing. Maybe when they killed the program, they manually added low-paying advertisers to this permanent list? But without the "passback" option, that would have been useless.

That is sort of what I was thinking of, because things used to be different and some things needed to be opted in and if you missed that it might have been considered 'blocked'. Waay back when they added Doubleclick I seem to recall it was opt in, iirc and that would be a ton of ads though I'd think things have been reconfigured since then.

It took a few hours, but I've gone through and removed all of the blocks. Most were junk (pointing to .IN or .RO sites, totally irrelevant with my target demo being in the US), but a handful were well known popular sites that should have never been blocked!

It's frustrating, since my CPC has dropped 84% in the last 4 years. How much of that was because bidders were being blocked that would have bumped up the value? I guess I'll find out in the near future :-/

Some years ago, Sulvo released a list of "Abusive Advertisers" and it became popular to use it.

May be you applied it, or, may be, at some point, you used a company to optimize your adsense revenues, and they applied this list. Some of these companies are asking access to your adsense account, to refine options....

Reference: [sulvo.com...]

Awesome catch, @Dimitri, that looks like the list on my end! I was specifically surprised when I saw established sites like astrology.com, inbox.com, nextag.com, openuniversities.edu, opera.com, spokeo.com, and winzip.com! But every one of those are on that list, so that had to be the source.

As I removed them all, it now looks like Adsense has a limit of 500. So I don't think I would be able to add that list back, even if I wanted to. After 6 years, though, I suspect that most of those sites are gone, anyway.

The same thing is happening to me with 6000 ads from good advertising brands blocked, I have never blocked anything.

I spent an hour unlocking and now there are no blocks of any kind.

Adsense automated bots are wreaking havoc on publishers.

For the sake of posterity, the day after I removed all of them my CPC increased 40%!

Then the next day it was back down to normal.

Coincidence? Maybe.