Update: It's official. Release here.

Earlier: We haven't heard the official details of the Yahoo-Microsoft search deal yet, but the ones we have heard sound distressingly complex.

Let's review what AdAge's Michael Learmonth has reported about the deal so far.

Michael's reporting is in black. Our comments are in blue:

Bing will become the default search engine on Yahoo. Fine.



Yahoo is likely to take on exclusive representation of Bing inventory to eliminate channel conflict and complexity for advertisers, but not before both sides unwind the thousands of advertiser relationships and proprietary systems through which many large advertisers buy search ads. Logistical nightmare. Will take years. Who is responsible to these clients in the interim? Who is responsible if the transition screws up?



Microsoft's AdCenter is expected to be the sales-technology platform. So Yahoo's sales force is responsible for sales and execution but they'll be using Microsoft's technology platform to do it. Add another couple of months. (What if the tech platform doesn't work right? Who will Yahoo's salespeople yell at? How will Microsoft's engineers feel when they're yelled at by Yahoo's ad salespeople? How quickly will they demand to be transfered to another Microsoft division, one where developers don't have to answer to Yahoo salespeople?)



Individuals close to both sides say they.. expect some antitrust scrutiny from the Department of Justice. Add another couple of months.

The deal will take Yahoo out of the search-technology business so it can focus on media, marketing services and sales. This is okay...as long as Yahoo has the ability to choose another search provider if Microsoft falls down on the job. If Microsoft and Yahoo are going to get this deeply intertwined with each other, however, that may be impossible. What kind of leverage will Yahoo have over Microsoft? What kind of leverage will Microsoft have over Yahoo? More complexity.



Microsoft, especially if it can cede search sales duties to Yahoo, becomes more of a technology and infrastructure company, its disciplines better aligned with its strengths. (It would still, however, have a massive global display-ad sales business.) Again, fine. But what about that display-ad business? Why is Microsoft still going to be in that business? What if Microsoft is unhappy with the way Yahoo salesforce is selling Bing? What if Microsoft's clients hate Yahoo, or vice versa? More complexity...



In return, Yahoo will retain the ability to sell search and have access to an even bigger pool of search data that it can use to target users with display ads. Okay, but Microsoft will be running the technology. So it will actually be Microsoft that has the ability to target users with display ads. Presumably the two companies will have to share this information. How? Systems integration?

Executives on both sides agree that the optimal structure for the deal would be to have one point of contact selling search inventory, but that will require restructuring vast departments with multiple heads at both Microsoft and Yahoo, which could take time. A lot of time. Who will get fired? How will they feel? How will Yahoo salespeople order around Microsoft tech people to get changes made? Who will those tech people report to? Etc.



Microsoft in particular is very concerned about the Department of Justice's reaction to the deal and they may seek its blessing. Just a formality--Justice would be idiotic to block this--but it will take time. And Google will fight it every step of the way.



Bottom line? It just sounds complex as hell--a management and logistical nightmare.

We await the official details... and hope there's more to it than what has been reported thus far.