The transition from Yahoo to the Microsoft adCenter is now complete, and marketers planning their holiday ad campaigns must remember to manage them through Microsoft.

Microsoft explains that this transition means all paid search ads for Bing and Yahoo properties are powered by the Microsoft adCenter. This means marketers have the chance to operate a single account in adCenter to reach a U.S. audience of more than 163 million searchers.

David Pann, the general manager of the Microsoft Advertising Search Network, says advertisers will want to closely monitor their campaigns over the next few weeks. He reminds marketers that the adCenter is auction-based, which means prices are set by demand. It will be important to assess which keywords have the best effect for campaigns, and Pann says prices will likely stabilize within weeks.

Microsoft also directs advertisers to its Transition Center to learn more about operating adCenter accounts.

For their part, Yahoo officials wish advertisers the best of luck with Microsoft-powered campaigns. In a blog post, the company reminds marketers that Yahoo will focus on delivering unique consumer experiences to help drive traffic into the Microsoft/Yahoo marketplace.

As Brafton has reported, the content in ads for Yahoo will be key as the company aims to offer a more "entertaining," visually focused user experience, and it will offer a new dynamic display ad format in light of its acquisition of Dapper.

Microsoft-powered ads for Yahoo may have an important effect on consumers – comScore says Yahoo sites are the third-leading "sticky" spots on the web, where internet users spend 9.5 percent of overall online time.