With CEO Carol Bartz at the Yahoo helm, Microsoft has finally managed to find an ally against Google on the search and online advertising markets. Announced earlier this year, the new anti-Google marriage is a victory for CEO Steve Ballmer who, at one time, even sought to buy the Internet giant to get closer to the Mountain View-based search rival. While the Microsoft and Yahoo agreement is under scrutiny by antitrust regulators in the US, a group of four ad agencies via an advertising industry association revealed nothing but support for the two companies that are set to rival Google.

The open letter is signed by 4A's President and CEO Nancy Hill, but also by Maurice Levy, Chairman and CEO, Publicis Groupe; Martin Sorrell, CEO, WPP; Michael I. Roth, Chairman and CEO, Interpublic Group of Companies; and John Wren, President and CEO, Omnicom Group. The heads of four major advertising holding companies noted that the integration of Microsoft and Yahoo search technologies could only be regarded as beneficial.

“A very important form of online advertising is search advertising – the sponsored links that appear when a search engine answers a query. A healthy, competitive market for search and search advertising is crucial to the Internet’s future,” reads an excerpt from the letter. “We believe that Yahoo! and Microsoft’s proposal to combine their technologies and search platforms is good for advertisers, marketing services agencies, website publishers and consumers.”

Hill noted that, while advertising was the fuel that powered the Internet, and the source of financial resources for many websites that offered their services or content for free, Google’s monopoly on the search market ensured that the Mountain View company also owned the lion’s share of online advertising. Google’s position will not change in any way in the eventuality that the Microsoft-Yahoo deal gets the green light from antitrust regulators. However, together, Microsoft and Yahoo can offer a compelling alternative to Google.

“These benefits are too important to wait for. As leading members of the advertising and marketing services industry, we urge the Department of Justice to bring its antitrust review to a speedy conclusion. This proposal enhances competition, and should be allowed to take effect as soon as possible,” Hill added.