Performance of 300 X 600 ad format

[numnum]

I've recently replaced a 160X600 ad with the newer 300X600 ad (text/images), and so far the only image ads displayed are 160X600, centered horizontally. But the CPC is better than it was. I'm wondering if the pool of bidders is larger for 300X600 than for 160X600 -- hence the higher CPC.

Anyone here also use AdWords and/or experiment with this newer format long enough to have a good idea as to whether this is the case? If it is, and if you can afford the additional 140px of horizontal screen space on your site, it would seem to me that 300X600 is the better choice. Also, I'm kind of liking the 160X600 ad centered in the 300px space -- it adds white space to the left and right, which helps the ad to stand out and the page to breathe a bit -- at least on my site.

[netmeg]

The 300 x 600 fit nicely in my sidebar on long pages, and I had some image ads that used the space too (never saw a 160 x 600 there though) and it earned. The problem was, when there was only one ad, it didn't collapse, which left a big gaping white space, and it's even worse on phones or tablets. So I took it off.

[glitterball]

The problem was, when there was only one ad, it didn't collapse, which left a big gaping white space, and it's even worse on phones or tablets. So I took it off.

Ditto - looks good when there's inventory, but when there is not....

[jpch]

I've tried it on 3 different sites at the same time. For whatever reason I got 3 very different results...Good, Bad, and Ugly. You might also see it display 2 300 x 250's stacked on top of each other in place of the 160/300 x 600 image. If it would collapse to a 300 x 250 when not filled I'd probably use it more. And when it's filled with 8 Text ads it looks terrible IMO.

[galapiat]

"The perfect is the enemy of good"

[sgod]

I just finished a one-week test of the 300x600 block. Over the week, it had about a 33% lower CPM than the 300x250 block I usually have in that spot (at the top of the right sidebar). The CPC was about the same, and the CTR was lower. Most of the ads I saw there were indeed 160x600 blocks with white space to the right and left, which I found found a little ugly but not horribly so. The one text ad I saw over the week was just one link with a lot of white space under it. I didn't like that too much.

Long story short, I have taken it down. It might be worth another try in six months.

[JS_Harris]

Try using lightly colored links on a darker unit background if your site has the typical white background. There won't be any whitespace below a single text unit when it happens. It's not as bad when there is actually a defined shape covering the area.