The Redmond company, which has a minority stake in the booming social networking site, said in a blog post that the companies are deepening their relationship in Internet search, working on new features and expanding into markets outside the United States. At the same time, the company says it will no longer be responsible for display ads on Facebook. Microsoft calls it a “mutual decision.”

“Given the kinds of advertisements that make sense within a product as unique as Facebook, it just made more sense for them to take the lead on this part of their advertising strategy,” said Bing general manager Jon Tinter in the post. “MS will continue to provide search advertisements to Facebook.”

The announcement coincides with the unveiling of a major Facebook redesign.