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PSA as first ad block but other 2 populated



9:23 pm on Aug 20, 2005 (gmt 0)

10+ Year Member

I just saw something that reset my understanding of how adsense works.
I have pages with 3 adsense blocks. The crawler should see them in order 1 then 2 then 3, as they are in a table one after the other.
I just bought up a page that hasn't changed for over a month and found the first add block was populated with a psa, and the other 2 blocks with real ads.
I also noticed on the same site that pages where all 3 ad blocks were previously populated when I opened the pages, only 1 block was populated. NO psa in the other blocks, just empty space.
Anyone got any ideas about this behaviour?


9:32 pm on Aug 20, 2005 (gmt 0)

10+ Year Member

Refreshed the page and this time all 3 ad blocks are populated. ... I wonder if this is a bug in the new code that decides how many ads to put in each block. The site does not get a lot of hits, so maybe they haven't tested this scenario.

Would this account for a problem I have seen others reporting that their sites get less revenue since the google change to making diffent numbers of ads appear in the ad blocks. This is a completely untested theory so don't hit me over the head for it. I just always thought, and google says it, that the most relevant ads are at the top. Hard to see how the first ad block could be a psa, and the most relevant, while the other ad blocks are populated.


1:06 am on Aug 21, 2005 (gmt 0)

10+ Year Member

I could be wrong, but I'm not sure that AdSense knows which ad block is being requested by the web browser.

The web browser makes the request (via the javascript) to the AdSense server -- the order in which the requests are made and received is partly dependent upon:
1) The order in which the requests are made
2) Web routing from your visitor's browser to the AdSense Server
3) Maybe some internal stuff going on at AdSense to try to correllate requests, timestamp them down to the millisecond, and try to serve the highest paying ads in the first request received, making the assumption that the browser requested the most important adblock first. (Not a perfect assumtption by any stretch of the imagination). Maybe not... maybe they just send back ads first come, first served with most important. Who knows.
4) I have definitely seen ad blocks carrying identical ads, which is against AdSense ToS, but how would I or any other publisher control such a problem? lol

I'd love to see AdSense add an optional field in the javascript for ad-block number (ie google_block_num = 1, 2 or 3) to let the AdSense server KNOW which is the more important block in the publisher's opinion.

Then Google would be able to correlate which adblocks on which page get better clickthrough rates (even if it isn't the publisher's #1), and send the higher-paying ads to that block, too.


2:05 am on Aug 21, 2005 (gmt 0)

10+ Year Member

I'd love to see AdSense add an optional field in the javascript for ad-block number (ie google_block_num = 1, 2 or 3) to let the AdSense server KNOW which is the more important block in the publisher's opinion.

Oh, wow. This is the BEST idea I've seen for an AdSense improvement since I started in January!

I hope ASA passes this idea waaaay up the ladder. :-)


6:23 am on Aug 21, 2005 (gmt 0)

WebmasterWorld Senior Member 10+ Year Member

Look carefully at the html for the page. If you are using tables, then it may well be that the first block adsense sees is not the first block the visitor sees on your page - hence the psa's in the wrong block.

This happened to me! I added a second block, and sort of assumed that because it was lower down the page it would be filled with grade 2 ads / psa's. That wasn't the case. The best payers moved to the lower block simply because I use a table on that page, and the main ad block comes lower down the html code than the lower block on the left of the page.

I then saw a post here that mentioned the "Table trick". If you Google for that then you will get the explanation for why, and what to do about it.


3:08 pm on Aug 21, 2005 (gmt 0)

10+ Year Member

Thanks YesMom

(Can I call you Mom for short?)

I've thought about that for a long time.

But alas, ASA doesn't seem to know I exist. ;)

Should I copyright and patent that idea? ;) I'll sell it to Google CHEAP!


3:23 pm on Aug 21, 2005 (gmt 0)

WebmasterWorld Senior Member 10+ Year Member

There can be other factors for PSA's, empty blocks, etc, such as there being no ads available at that time, or maybe the ads went to other sites with higher CTR.

The 2nd and 3rd blocks may have show ads instead of the 1st block because the content surrounding those blocks may have been more relevent to the available ads.

If i was getting psa's on a page with multiple ad blocks i would get rid of one or two blocks.


4:31 am on Aug 22, 2005 (gmt 0)

WebmasterWorld Senior Member 10+ Year Member

Hi RonS -

Thanks for the about allowing publishers to prioritize ad blocks. I have, actually, passed this thread along to the product team. ;)

Feel free to shoot me a sticky mail if you have any other ideas and want to make sure I see them! I try to read everything, but I probably miss things...



12:11 am on Aug 23, 2005 (gmt 0)

WebmasterWorld Senior Member 10+ Year Member

Also, as many of you know already, you can use custom channels to track the performance of each of your ad units to see which ones are performing most effectively.

If you're interested in doing this, see the following page for more information:




7:24 pm on Aug 23, 2005 (gmt 0)

10+ Year Member

No offense, but what does that have to do with AdSense knowing how to place the most appropriate/highest paying ads in the proper position on the page?

Sure, I could create 3 different channels for each page (for up to 66 pages) and track which is performing best, and in fact, I do but not on a individual pages, on a series of template-driven dynamicly generated pages.

I find that I do NOT get the highest PPC on the ads in the top position, where I get the highest CTR!
This is based on 2 different sections of a site with 45,000 and 8,000 page impressions in July.

(In August, so far that has reversed, but August has been a VERY strange month for me, starting off very nicely, then declining very sharply on the 10th...)

If G would put the highest paying ads on the proper place on the page, we'd be making more money, perhaps.

(Want to see the stats, ASA? Sticky me. (ASA only))


4:16 am on Aug 24, 2005 (gmt 0)

WebmasterWorld Senior Member 10+ Year Member

i have also noticed this kind of adsense behaviour on my sites since about two months.
on one site, i have up to three identical ad blocks and sometimes only the first or second or third is busy. sometimes i get only one ad in the first block, but four in the second and so on..
it randomly changes from visit to visit and from day to day. sometimes it's like it should be, sometimes not.
very strange!

explanation: technical processes

as i said, i haven't encountered this phenomenon before and haven't changed site layout. also, the ads occur in the html-code strictly one after another.
i know of strange javascript behaviour, but in this case i doubt the correlation.

of course there could happen internal stuff on the google adsense server.

my question is: is it in fact an accidental technical instance or is it intended by the adsense system (content based)?

if it is intended, that would of course negate the dogma, that highest paying ads occur on the first block on the page respectively on the block which is encountered first in html code.

surprisingly this kind of ad-switching between the blocks seems to have no negative effect on my earnings.

and it doesn't occur all the time, so my thougt: is google playing with ad placements recently?


6:07 pm on Aug 24, 2005 (gmt 0)

10+ Year Member

My site with the most income from Adsense ads are now (last 3 days) suddenly showing PSA's and CTR went down from a normal 8 to almost nothing.

Anyone else has experiencing something like this?


4:35 am on Aug 28, 2005 (gmt 0)

WebmasterWorld Senior Member 10+ Year Member

ok, worth reading the adsense blog from time to time:

[adsense.blogspot.com ]

"We've updated AdSense to now vary the number of text ads that appear in a given ad unit. When we have a set of highly relevant and useful ads, we give them more of a presence in the ad unit by eliminating other ads. In some cases, if we determine a particular ad performs extremely well on a page, we'll remove all other ads from the unit and show just this single ad."

why didn't the adsense team inform us? i think this is an important update and maybe some publishers felt confused with what has happened to their ad blocks?


4:45 am on Aug 28, 2005 (gmt 0)

10+ Year Member

have you been in a cave? the news was posted on everyone's account weeks ago. even many threads started here during that time with the new changes..


5:10 am on Aug 28, 2005 (gmt 0)

WebmasterWorld Senior Member 10+ Year Member

excuse me, didn't notice that in the threads and in my account..


5:21 am on Aug 28, 2005 (gmt 0)

10+ Year Member

sorry if i sounded rude., it was right on the front page of adsense account when you login (dunno if it's still there).

edit -


5:54 am on Aug 28, 2005 (gmt 0)

10+ Year Member

I have 3 script blocks one above the other, (in the code and layout, all within the same div). I've seen this behaviour too and been confused by it.

My work-around is just to include collapsible ad units instead of the PSAs or alternate ads, this way (unless by some quirk of fate all 3 are PSAs), the top ads still appear at the top.


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