Social networking site Facebook is putting a different twist on online classifieds. Rather than spamming friends and family with garage sale "junque," users are encouraged to turn P2P selling into a conversation and even, in some cases, entertainment.

Facebook Marketplace powered by Oodle launches today (March 3rd). Users can add the application to their Facebook and very quickly list an item. A simple form consists of standard fields: What you're selling, the price, location, category and description, and a feature that allows users to upload photos. The field that makes Facebook Marketplace different from other online classifieds is, "Why are you selling it?"

According to Oodle CEO Craig Donato, answering that question in the listing can prompt users' friends and family to create a dialog. Commenting on the listing itself can also turn into a spontaneous FAQ (frequently asked questions) so sellers aren't forced to answer the same question over and over - comments appear in a section of the listing.

Once a user creates a listing, it appears in their feed, shown to all friends and thereby integrating it into the Facebook experience. Users may also go to the Marketplace directly where they can conduct searches among all listings. (Donato said they will be adding functionality so users may limit listings to display to friends-only if they choose.)

Have something sitting in your garage that you don't want to sell? You can "Give it away," or "Sell for a cause" - a feature that allows users to raise money for over a million registered 501(c)3 charities. (Oodle is working with Network for Good to collect payments and distribute funds to the charities.)

You can also "Ask for it" - Donato said a user might create a Marketplace listing to advertise that they are looking to borrow a power washer, for example. He said Oodle "diverged from the classic script" when building Facebook Marketplace and would have failed if it had forced Oodle into Facebook.

Facebook first introduced its Marketplace application in early May 2007 as a way for Facebook users to post listings across categories such as "Furniture" and "Roommates." To further expand the functionality and breadth of the application, Facebook selected Oodle to build and power the new marketplace because of its experience with online classifieds and building sites for large partners.

There are 170 million Facebook users, and there is no charge for using Facebook Marketplace.