Google Adsense Large Rectange format are now displaying the normal 4 ads. I think we might see a drop in eCPM but at the same time, an higher CTR.
I don't think that's the case. Read this Google reponse in the Official Adsense Blog. Malcolm asks: I have noticed that the number of ads displayed in my large rectangle ads has dropped form 4 to 2 ads. Do you know why this is? We say: It sounds like you're seeing expanded text ads appearing on your site. Our technology optimizes the number of ads per ad unit to ensure your site's revenue potential is maximized. When AdSense determines that fewer ads will perform better in a particular ad unit, the lower paying ads are automatically dropped.
Well, I just kind of assumed that a page with a lot of content is more likely to have 4 higher paying ads displayed were as a page with less content will have 2 higher paying ads displayed. This isn't always true though. Either way, they have not switched from 4 to 2 or from 2 to 4, it depends on the page.
Riboflavin, it was widely reported about a month ago that Google started displaying 2 ads instead of 4 in the 336 x 280 (large rectangle) ad format. I can personally attest to this having seen this on my own site. This had nothing to do with content as large rectangle ads as well as other ad formats appearing later in the source code of the same web page displayed their full complement of ads. This was definitely a Google experiment with an increased proliferation of the so-called 'expanded text ads'. When I first saw it, I didn't like it because it blew away my layout (all that white space) and I thought my CTR would drop but this didn't pan out. Actually my CTR held steady and my earnings increased (although I was forced to modify my layout to accomodate the new format). Now that they've switched back (I'm seeing the same changes as noted by amitpagarwal in the launch post), my layout is all messed up again. I wish Google would make up their minds.
My biggest issue with this to...is that it keeps messing up layouts, I'd like to see it remain consistent. Can't complain to much, when they pay me most of my monthly cash.