The fact that the matter is....in order for the CPM ad to display...

[asianguy]

the advertiser has to outbid the combined total bids in one ad unit in order for the full size ads to show up. At least, this is what i think about it.

After all, Google is not that stupid to innovate things only to lose revenue because the publishers are leaving.

Advertisers will soon opt out and switch back to PPC because their ads never showed up, or ROI is bad.

Likewise, basing from previous reports, PPC always outperfom CPM.

[europeforvisitors]

Google is not that stupid to innovate things only to lose revenue

That's what I think, too.

Advertisers will soon opt out and switch back to PPC because their ads never showed up, or ROI is bad.

Or maybe they'll just bid more, depending on what they're trying to accomplish and what audience they're trying to reach.

[ownerrim]

I guess this depends on the astuteness of an advertiser, and how much an advertiser would like to appear on a particular site. One way to stoke the fire might be to send an introductory letter to the advertisers appearing on your site--unless this is currently against adsense tos

[cyanweb]

CPM ads will most likely become used for image based ad areas... where competativeness amongst the big brands will drive CPM to a respectable level...

It stands to reason that yes - Google doesn't want to lower it's revenue - so PPC will still be the preferred ad shown unless a "higher performing" CPM ad is available...

Note: that's "higher performing" not necessarily "higher bidding"