In the wake of the changes at Microsoft’s online division, a senior advertising sales exec, Bill Shaughnessy (pictured here), is set to leave his post, the company confirmed.The departure was first reported in Ad Age, which said Shaughnessy’s future plans were undetermined and, in fact, noted it was unclear why the longtime Microsoft (MSFT) staffer of 15 years was leaving.BoomTown found the answer looking at the very bottom of the press release announcing the hiring of former Yahoo (YHOO) tech exec Qi Lu as head of its online services group:“As part of today’s announcement, several teams will move to further align resources. The field sales organizations in the Online Services Group will move to Microsoft’s centralized Sales, Marketing and Services Group led by chief operating officer Kevin Turner. This group, called Consumer & Online, will be led by Corporate Vice President Darren Huston and will include the Global Advertising Sales and Services organization, led by vice president Bill Shaughnessy.”The move to centralize, according to sources, has been controversial within the company, since that means all sales are being lumped into one mega-group. Shaughnessy has worked on a range of MSN properties, as well as for the Windows group.In his most recent job, he worked closely with Brian McAndrews, the top online ad sales exec at Microsoft, who announced he was leaving the company on the same day Lu was hired.McAndrews had been a contender for the digital head job.According to a Microsoft profile of him, Shaughnessy was global VP of sales, marketing and services, “responsible for the business leadership and management of its international business operations outside of the United States, including the Greater Asia region. His responsibilities include sales, marketing, business development, programming and regional and country management.”