Social networking site Facebook has acquired Friend.ly, a social question-and-answer service, for an undisclosed amount.

The two-year-old start-up, Friend.ly, has designed an app for Facebook that helps users pose questions to online friends.

Friend.ly announced about the buyout on Monday in a blog post. However, it did not give the financial details of the transaction.

Friend.ly said it will focus on new projects at Facebook, but will continue to operate as a separate service.

"We are excited about this because we feel the spirit of Friend.ly aligns well with Facebook's vision and we are thrilled to be joining such an innovative company. The Friend.ly team will be focusing on new projects at Facebook, but friend.ly will continue to operate as a separate service," the start-up firm said.

Friend.ly, a California-based company, has 10 employees, while Facebook has about 2,000.

It seems that Facebook is on an acquisition spree and is believed to made 10 purchases last year. In 2009, it made just one acquisition.