Craigslist has outlasted its challengers, and remains the platform to beat for classifieds, or “things to sell” marketplaces. eBay, similarly, remains a leader for the sale of goods – although most are not geographically oriented. Amazon is also active in that space.

Can Facebook, with its huge volume and trust networks, cut into their business? It is going to try via a new “For Sale” offering that allow users of its groups to post items for sale. Items are listed with prices, photos, descriptions, pick-up location and prices. They can also be listed as “available” or “sold” to let buyers know what’s still on the market/

The listings are currently free — and probably won’t go into the paid areas that provide the bulk of Craigslist’s revenue: apartments, cars, jobs and “personal services.” But if Facebook decides to provide a greater emphasis on classifieds, it could conceivably move into transactions (and commissions). It could also open the service up beyond its groups to have more of a geo-orientation.

It isn’t the first time that Facebook has been used for classifieds. Oodle, a large classifieds platform that launched in 2005, took over a nascent Facebook classifieds service in 2008 and focused on Facebook’s huge scale to offer items for sale to friends and groups within the service. Oodle was sold to QVC several years ago.

It also isn’t the first time that online groups have been used for classifieds. In their heydays, Yahoo Groups and Big Tent — each with hundreds of thousands of users — had active lists of classifieds. Many associations and groups currently host classifieds on their websites and pages.

The classifieds project is the latest transaction-oriented effort from Facebook, which may want to diversify its revenue beyond advertising. Facebook has been experimenting with various transaction models for several years, including tests with virtual gift cards, deals and virtual currencies. Facebook has also developed an Amazon-like capability to enable transactions on other sites by collecting credit card information on its profiles.