James Martin/CNET

Facebook and Microsoft's relationship status? You can say "It's Complicated."

The social network said it is no longer relying on Bing for Web search results, ending a four-year online relationship with Microsoft's search engine. Microsoft still owns a tiny but valuable stake in Facebook.

"We're not currently showing web search results in Facebook Search because we're focused on helping people find what's been shared with them on Facebook," a Facebook spokesman said in a statement.

Microsoft also confirmed the move, practically echoing Facebook's statement. "Facebook recently changed its search experience to focus on helping people tap into information that's been shared with them on Facebook vs. a broader set of Web results," a Microsoft spokesman said Friday.

Both companies stressed they continue to partner in other areas, however.

The pseudo-breakup is both surprising and expected. Facebook has been building its own search technology, focused primarily on helping users find information within its social network. Two years ago, the company unveiled Graph Search, a way to sift through friends with queries like, "College classmates who like Coldplay and X-Men movies and live in San Francisco."

To Mark Zuckerberg, Facebook's CEO, search is one of the most important initiatives happening at his company. He also expects search, as well as Facebook's Instagram photo messaging service and WhatsApp messaging program, will reach 1 billion people within the next five years. "Once we get to that scale, then we think that they will start to become meaningful businesses in their own right," he said in an October conference call.

The move is also a blow to Bing, Microsoft's answer to the world's top search provider, Google. Industry researcher ComScore said that as of October, Google represented 67 percent of Web searches, while Microsoft's Bing represented nearly 20 percent. How much Facebook will affect Bing's market share is unclear.

What is clear is that Facebook and Microsoft's relationship isn't as strong as it was seven years ago, when the software giant acquired a 1 percent, $240 million stake in the social network, valuing the company at $15 billion. Today, Facebook is valued at more than $211 billion. So, there's a lot left for Microsoft to like.