The companies did not reveal the purchase price.
As is typical with Google acquisitions, Metaweb said it plans to support existing customers but won't take new ones while it integrates with Google.
It will be interesting to see whether Google rival Microsoft continues to use Metaweb. According to Metaweb, Bing uses Metaweb to provide Instant Answers in its search results and in visual search. The Instant Answers feature displays answers to questions at the top of the Bing search results page, before the results listing.
Microsoft did not immediately reply to a request for confirmation about its relationship with Metaweb or its intentions following the acquisition.
Google said it believes Metaweb can help it offer better answers to more complex questions that people pose to search engines. Google can offer answers to factual queries such as "Barack Obama's birthday" because it understands facts about real people and events, Jack Menzel, director of product management at Google, wrote in a blog post about the acquisition.
But searches for phrases such as "colleges on the west coast with tuition under $30,000" are more difficult to respond to, he said. "These are hard questions, and we've acquired Metaweb because we believe working together we'll be able to provide better answers," he said.
Current Metaweb products include embeddable information boxes on any topic that customers can add to their websites or blog posts, a tool that lets website operators query certain content sources, such as Twitter and Hulu, and custom data feeds.
Metaweb also hosts an open database called Freebase that contains information about 12 million people, places and things. Anyone can contribute to the database and anyone can license it, using the data on their own sites.
Google said it plans to continue to maintain Freebase as a free and open database and expects to further develop it.
