If successful, it's conceivable that these major brand advertisers would increase their digital advertising spending in order to participate in the AOL/Yahoo/Microsoft project, in addition to the money they spend on premium "tier one" display ads.
"If we have access to 'premium' unsold inventory it can be a very positive influence in the way we're buying media and it will accelerate the audience buying trend as it exists today," Montgomery said.
The deal is expected to go into effect in early 2012, once the companies have integrated their real-time bidding systems so they can tap into each other's ad networks -- Yahoo Network Plus, AOL's Advertising.com and the Microsoft Media Network.
The project will also include ad inventory from third-party publishers that already participate in the Microsoft and Yahoo ad networks. It's not clear if third-party publishers associated with AOL will be included. An AOL representative didn't immediately respond to a request for comment.
For publishers that aren't part of Microsoft's ad network, Microsoft would structure deals on a case-by-case basis to include those who are interested in participating in the initiative. "Since the agreement is so fresh and won't be operational until next year, we haven't begun those discussions yet," a Microsoft spokesman said via email.
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