The proprietors of the Facebook social media Web site say they have launched a new search engine allowing users to sort postings by keyword.

The feature enables users to search not only posts made by their "friends" but also by anyone else who has made public comments relating to the keyword, The Wall Street Journal reported Tuesday.

In preparation for the search function, Facebook has reportedly been urging its 250 million users to share more public information. The Web site also announced Monday it had acquired another social media Web site, FriendFeed, which sports a much-acclaimed search technology, the newspaper said.

The Journal reported that Facebook, based in Palo Alto, Calif., hopes to draw more advertising with its new search feature, which they said will keep people on the site longer and allow them to be more accurately targeted by advertisers.

Other search engines such as Google are also moving to improve their products. The company announced Monday it has introduced a new version of its search service based on a new infrastructure that reportedly is meant to "push the envelope on size, indexing speed, accuracy, comprehensiveness and other dimensions."