Last night Facebook availed Groups, Wall Posts, Events and Discussion topics to search engines for indexing purposes, reports All Facebook.

The move effectively converts Facebook's consumer-generated trove of categorized content into a search engine optimization source, and is expected to draw more traffic to the site from organic searches across Google, Live Search and Yahoo.

In the interest of privacy, only public groups and events will be indexed. And it isn't yet clear how much personal data will also be open to indexing. A survey conducted in summer of last year found Facebook users are surprisingly liberal about listing sensitive personal data on their profiles, including likes and dislikes, employer details, date of birth and — in some cases — even mobile numbers. All of this is available to those users add as "friends" or people in their immediate networks, depending on their privacy settings.

A recent comScore study also found Facebook and rival MySpace have joined the ranks of the fastest-growing search engines, both because individuals post so much personal information and local events data, and because they spend so much time searching for the personal information or events listings of others.

MySpace, whose search engine is powered by Google, accounts for more searches than eBay, Craigslist, Facebook and Amazon. Facebook is also beginning to tap into the merits of its information ecosystem, with plans to integrate Microsoft's Live Search engine by year's end.

On search sites like Google and Yahoo, search has proven a lucrative vehicle for advertising. Social media sites, which have so far proven difficult to monetize, may stand to benefit from the sponsorship opportunities of improved search capabilities. That they also boast a great deal of frequently-updated, relevant content contributes to their capacity to contend in the search space.