Yesterday the news came out that ad network AdMob had acquired the assets of "mediation layer"/aggregator AdWhirl. This likely sets the stage for an exchange play (in earnest) by AdMob, analogous to what Yahoo has with RightMedia on the PC.

AdWhirl enabled iPhone developers to sign up for ad units/inventory from a wide range of ad networks, to improve fill rates -- it was promising 100% -- and optimize CPM/CPC revenue in addition. At one point AdMob had said it was no longer going to work with AdWhirl but later decided not to go through with that move. Now the former has bought AdWhirl. 

Deal terms where not disclosed. AdWhirl had reported $1 million in funding and so I'm guessing that the purchase price was south of $10 million (perhaps several million shy). Reportedly AdWhirl will now expand to encompass other apps platforms, including Android, BlackBerry and so on. 

In expressing its objections to AdWhirl's methodology at the time, AdMob VP Ali Diab said in a blog post:

What we have also found over the last few months is that mediation layers significantly impair AdMob’s ability to optimize the selection of ads for the apps that choose to use them, by obstructing our view of these applications’ traffic profiles. These traffic profiles are a key input parameter that we use at AdMob to select the right ad for the right app at the right time.  By working directly with the publisher, AdMob is able to generate a much more accurate profile of the traffic, in terms of both volume and timing, generated by a specific iPhone app, which will enable us to optimize the revenue potential that we can deliver for the app.

Now AdMob has embraced the "mediation" concept, perhaps shrewdly so. AdWhirl can now be the basis of a broader marketplace or exchange that will reach multiple smartphone platforms. AdMob thus gets a kind of "hedge" if the mobile ad market should start to heavily favor exchanges vs. networks. Other networks, such as Quattro, have been experimenting with delivering third party ads along with their own to publishers. 

AdMob CEO Omar Hamoui provided the following statement to TechCrunch:

Our open source solution will be both for the client and the server. We anticipate there will be many independent servers run by developers, and possibly our competitors as well. Once we release the code into the community, we think it will be adopted widely.

Most developers use mediation layers for percentage based inventory allocation. This is not something that you can game or manipulate. The mediation component either fulfills the percentage allocation or not. We are committed to making this solution as open as it needs to be to make everybody comfortable. We also expect the market will hold us accountable to this course of action.

The AdWhirl team has visited our offices over the past several days as we have worked through this deal. However any claims that we have historically been sharing data with AdWhirl or manipulating how it works for our benefit is completely false.

Since the news broke we’ve been talking to developers and they agree that the key is an open and transparent solution. We expect to be held to that.

The article in which that quote appeared asked the question whether AdMob would maintain AdWhirl as a "neutral" exchange or whether it was going to favor its own advertising. Commenting on the deal, along those lines, Greystripe CEO Michael Chang said the following about a potential "conflict of interest" for AdMob:

“We believe that it is a conflict of interest for an ad network to own a mediation company. A mediation company needs to be a separate entity to do its job of unbiased optimizing of a number of ad networks.”

If AdWhirl does remain neutral and open as AdMob CEO Omar Hamoui promises it should continue to thrive. If it becomes biased toward AdMob's own inventory or in some other way, new "meditors" will rise up to replace it.