I tend to keep all categories open, but I block a lot of URLs. From time to time I experiment with unblocking them, but generally find my site and earnings are better with my block list in place.

I mostly only block stuff that isn't family friendly (which is too bad, but if you have ONE site that kids might visit, that's what you gotta do) and stuff where Google can't figure out synonyms and/or advertisers aren't aware enough to realize they shouldn't be showing their ads on my sites.

@numnum, I block some because my main audience is male, but when I blocked "low performing" categories, my eCPM went into the toilet.

@numnum, I block some because my main audience is male, but when I blocked "low performing" categories, my eCPM went into the toilet.

Do you use the term "low performing" in the same sense that I would, based on my original post for this thread? If so, then one might conclude that when you block enough habitually low-performing ad categories you'll wind up trashing your CPC so that your total earnings will actually decline despite the fact that you've blocked low performers. Why? It's the advertisers pushing products and services irrelevant to your site's topic who have the deep pockets and hence help bid up the prices for ad space at your site. Am I right about this?

I suppose I'll just have to try category ad-blocking as an experiment, and watch what happens. I'm surprised more Adsense publishers here have not experimented with ad blocking by category in a systematic manner to determine the point at which this sort of blocking becomes counter-productive.

Until March 23, I wasn't blocking many ads. A few certainly, but each time I blocked the scAmmy ads my earnings and CTR tanked. Since March 23, my visitors seem savvier than ever. Blocking the scammy ads has raised both earnings and CTR.

It's amazing how your audience can change if your rankings slip even one or two positions.

As of today, my traffic is down about 20% but income as almost back to where it was. Needless to say, I was very busy last week ;)

I gave up years ago. I'm not wasting valuable time going through stupid irrelevant ads.

Yes, weight reduction programmes, dating sites and other krap were OK to AdSense for my genre.

I'm NOT vetting individual ads anymore. I get to that stage then I take AdSense off my sites.

I Block many categories, Just because i don't like those categories, If there was no blocking option, i might not use adsense at all. I wish i had more control. My Earnings are healthy, Blocking reduces your earnings is a biggest lie.

I mostly only block stuff that isn't family friendly

Site's using AdSense aren't supposed to have content that isn't "Family Friendly" on them so seems a little hypocritical that Google would serve ads considered not to be "Family Friendly". I hear what you're saying netmeg but hopefully you understand the irony in what you're doing. This is why I wish Google wouldn't use vague definitions like "Family Friendly"...because everyone has different standards of what that is.

Not much gets past me.

And what Google considers to be family friendly and what my users consider to be family friendly aren't necessarily the same thing. The only problem I have with Google in this regard is that they won't let us block ads on a per site basis. I have a lot of sites, and what's appropriate for some aren't appropriate for others.

Nummum I'm curious as to whether you have done any testing on this over the months since your original post.

One reason category blocking might reduce revenue overall is that there is not an unlimited amount of ad inventory. There are only so many ads per ad type, ad size, etc. and if the ads are contextual, that limits things a bit further.

So I would speculate that "under-performing" category blocking given your original definition of under-performing would increase revenue with two caveats. 1) there is an unlimited supply of potential ads 2) you are not blocking categories that have a strong contextual connection to content on your site.