Carolyn Everson, vice president of global advertising sales and trade marketing for Microsoft, is leaving the company after just seven months. Everson was responsible for the multibillion dollar ad campaign for the launch of the Bing search engine.

Facebook confirmed Everson’s hiring yesterday, and noted that she will report to a former Google employee, David Fischer, Facebook’s vice president of advertising and global operations.

This move may make things a little awkward since Microsoft invested over 240 Million in Facbook back in 2007. Facebook released the following statement:

“Microsoft was one of our earliest partners and is still one of our most valued. We have a long and strong relationship that includes search ads on our site, a social layer on Bing search results, and a deep and popular integration with Xbox. They are a leader when it comes to unlocking the power of social for their already popular products and services. We look forward to continuing to expand our relationship with them.”