Microsoft exec who led Yahoo buyout team to leave

After a short transition, Johnson will step into the role of chief executive officer at Juniper Networks Inc., a networking hardware maker, according to a person familiar with the situation.

The person asked not to be named because Juniper had not yet announced Johnson's appointment.

Johnson has served since 2005 as president of Microsoft's platforms and services division, which included the Windows operating system and Windows Live programs such as Web e-mail and instant messaging. The division also included online advertising, search and Microsoft's MSN sites.

Johnson, who joined Microsoft in 1992, has been the public face for the company's search and online advertising strategy, meant to help the company catch market leader Google Inc., since starting the job.

It was Johnson who laid out Microsoft's aggressive goals last November that included capturing 30 percent of U.S. search queries.

Over the last year, as it became clear that Microsoft's internal search and advertising efforts were not propelling the company forward fast enough, Johnson was at Chief Executive Officer Steve Ballmer's side while Microsoft attempted to buy Yahoo outright and, when that failed, to buy the Silicon Valley icon's search operations.

He also spearheaded the $6 billion acquisition of online advertising company aQuantive in 2007. Incorporating aQuantive has boosted Microsoft's Web ad revenue, but not enough to put the software maker in league with leader Google Inc.

"Whether it was his decision to leave, or whether it was based on recent events probably related to Yahoo and the online segment's last-quarter performance, I don't know," said Matt Rosoff, an analyst for the independent research group Directions on Microsoft.

Last week, Microsoft said its online business lost $488 million in the quarter, more than double its year-ago loss, and announced hundreds of millions of new spending to try to turn the operations around.