Microsoft has not yet acquired Yahoo!, but Kevin Johnson, Microsoftis president of the Microsoft Platforms & Services Division has published an open letter that aims to put concerns at ease, including the fact that Yahoo! is a non-Windows company.

"We believe our proposal is a compelling one and that the combination of Yahoo! and Microsoft creates a more credible alternative to an increasingly dominant player in the advertising industry," Mr. Johnson said for openers.

The letter proposed to answer questions, but may have also been designed to slow down the personnel flux in anticipation of the merger. As might be expected, Mr. Johnson also explained how the merger would benefit consumers, developers, advertisers, publishers, and shareholders.

Letters like this also typically try to reassure employees about the potential culture clash between two alien companies. Of note was this Q&A pair:

Q: If we move forward with a combination, what’s our plan for addressing Yahoo!’s technology infrastructure, since it’s non-Windows based?

A: Services weive acquired over the years have been based on both Windows and open source technologies. Although Windows is our strategic platform and in some cases the teams ultimately migrated their products to Windows for a variety of reasons, in other cases we have prioritized continuity and have used open interoperability mechanisms to achieve effective systems integration. Yahoo! has made significant investments in both its skills and technologies, so we would work closely with Yahoo! engineers to make pragmatic platform and integration methodology decisions as appropriate, prioritizing above all how those decisions would impact customers.

In the past, Microsoft has run ads showing how Windows deployments are less expensive than Unix deployments. Just how that would factor into "customer impact" will be interesting to watch if the merger is successful.