"We have signed a definitive agreement to acquire Aardvark, but we don't have any additional details to share right now," said a company spokesperson in an e-mail.
Google has not confirmed a price, but a report on TechCrunch says that Google will pay about $50 million.
Aardvark is a matchmaking service for questions and answers. It allows users to submit queries and then connects the searcher to friends or associates who are likely to have the best answer.
By acquiring the company, Google is deepening its already substantial commitment to social networking -- an interest evident in the launch of Google Buzz earlier this week -- and is expanding beyond algorithmic problem solving toward services with more of a human component.
And a greater emphasis on people might be just what Google needs: The company's focus on data, automation, and scalability has meant that the people-oriented side of its business, such as customer service, often comes up short.
In a blog post last week, Aardvark's CTO Damon Horowitz acknowledged the company's debt to Google. The paper in which Google co-founders Sergey Brin and Larry Page describe their PageRank algorithm, he said, was the inspiration for a paper that Aardvark submitted to an upcoming technical conference, "Anatomy of a Large-Scale Social Search Engine."
Speaking at an event called TEDxSoMa in January, Horowitz sounded like the ideal candidate to help turn Google into a social network. "The primary goal for technology should not be replacing human intelligence," he said. "It should be facilitating human interaction."
Google's last social networking acquisitions, Zingku and Jaiku, occurred in September and October 2007.