No.

Then why does my AdSense revenue vary +/- <1% each month when traffic is significantly different?

BTW I'm not complaining, while it's far from the old glory days, it's still very healthy.

Minimum acceptable to AdSense?

Then why does my AdSense revenue vary +/- <1% each month when traffic is significantly different?

If we assume that the advertising budgets remain the same month over month, then the CPM will go up and down when the number of impressions gets lower and higher respectively.

So, yes, there is a glass ceiling. You can see it as an equilibrium point where supply (OF ad spaces) and demand (FOR ad spaces) curves intersect.

I vote yes... Just a gut feeling I have, having seen more traffic, more clicks and end up with almost the same monthly income.

Oh, and like IanCP said I'm not complaining either! (well ok I am but what can you do!)

I don't believe in any glass ceiling, because there's no valid reason for it, from a business standpoint. It would be lose/lose/lose for publishers, advertisers and Google.

Much more likely is an "organic" ceiling of sorts, in which some smaller niches may achieve a certain threshold and then stay there, unless the publisher figures out how to diversify, attract more (and new) advertisers, and more (and new) audiences.

We've seen some decent growth this past year with the addition of the larger font sizes in the ad units. Hence it seems to go against the glass ceiling theory, since we are climbing higher each month along with our traffic.

No glass ceiling at all here.

I have touched what I think was a glass ceiling in a minimal niche in the past. Diversifying the content attracted more advertisers with broader product and service ranges and therefore there is no ceiling visible at this moment.

At one point I was beginning to think there was a glass ceiling but I've been with AdSense since '03 and every year has been better than the last in terms of overall earnings so I don't believe there is one. CPM, CTR, etc. that will fluctuate, and you only have a limited amount of control over AdSense earnings, so spend your efforts focusing on what you do have control over, which is your site(s).

Has anybody even remotely considered the possiblity that this 'glass ceiling' is merely a manifestation of fixed advertiser budgets?

...traffic goes up, it goes down...

The glass ceiling question is a legitimate topic for discussion. It's upsetting to see an uptick in traffic without an accompanying rise in earnings.

Not all traffic is the same. The reasons why people visit your site vary and so does the likelihood of a visit turning into a click. The answer to why people visit your site is in various metrics within your daily traffic logs. Some keyword phrases are better than others. Some pages deliver better earnings than others.

I noticed a spike in traffic to one of my pages caused by a number one ranking for a phrase. I studied that page to see what might be slowing down the clicks for that keyword phrase, made some changes and income went up. Now I'm going to make the same change across the rest of the pages in that particular section. No glass ceiling here. ...somewhat.

As someone else suggested, some niches have limited ad inventory. Even in the above example where I improved earnings, there is a ceiling to how much improvement I can make. An examination of the ads last night made clear that a lack of inventory was keeping some visitors from becoming clickers.

[edited by: martinibuster at 11:18 pm (utc) on Jan. 29, 2010]

Has anybody even remotely considered the possiblity that this 'glass ceiling' is merely a manifestation of fixed advertiser budgets?

that's what I'm telling :)

One simple thought. On a given page if the page performs very well (earnings wise) one day, and Google has a large ad inventory, the quality of the ads the next day may not be as good, lowering your CTR and earnings the second day. In this way Google can rotate a large ad inventory giving every advertiser a shot at displaying an ad on your pages no matter how low the bid. This technique would tend to pay your page the average bid from all the bids; unfortunately giving you average earnings. Google has to give all the bidders with reasonable landing pages a shot at placing their ad on your page.

I believe the concept that the highest paying bid is always in the first add block, is long gone.

When I did a detailed study of my ad earnings, I've was surprised to find a propensity for the second ad block on a page (in coding order) to earn more per click than the first ad block. The difference is very small. I did play with absolute positioning for a while but it just wasn't worth it, PLUS, I was probably pushing the terms of service TOS.

I think one has to look at the traffic/income level before looking at relatively stable income. For example, if you make just a few bucks a day then the swings can be huge percentage-wise. For instance, if someone makes just $10 a day and then sees a drop to $8 that will be huge swing but websites that earn 3-4 digits a day are likely to see swings of just a few percentage points because not only do they have more stable traffic (running into tens of thousands daily) but also a wider topic base with visitors from many different geographies to make income more stable. I can confirm that there is no ceiling because I have grown over the years as traffic has grown and new content has been added.

That's a good theory Bumpski. I've been with Adsense many years and in the "olden days" the top ad paid more than those lower down. Now, teh lower down ads pay the same.