Four new as-of-yet undocumented methods appeared in the Facebook API Tool to developers today, indicating that applications will be able to read listings from the Facebook Marketplace. No word yet on further details, such as whether or not an extended permission will be added to enable write access, allowing applications to post listings*.

• marketplace.getCategories - returns an array of all available categories (currently: forsale, housing, jobs, other, free, forsale_wanted, housing_wanted, jobs_wanted, other_wanted)
• marketplace.getSubCategories(category) - returns an array of subcategories, (calling this with “FORSALE” returns: books, furniture, tickets, electronics, auto, general)
• marketplace.getListings(listing_ids, uids) - returns one listing, as described in the search method
• marketplace.search(category, subcategory, query) - returns an array of results. results are an array with the keys listing_id, url, description, price, poster, update_time, category, subcategory, image_urls (an array of urls)

This functionality will be helpful to applications that involve goods, but unfortunately for the developer, no money can be made from these free postings. If I have a book reviews application, for example, now I can share with my users marketplace listings where they can buy the book, but as a developer, I won’t make any money from doing so. This once again echoes the worries of developers (1,392 words) that monetizing on Facebook might prove to be too challenging. However, at least while developers scramble to figure out how to monetize their applications, the users will benefit from easier access to another useful, free feature of Facebook.

*Update (10/13): The API Tool now shows two more methods which use extended permissions, marketplace.createListing and marketplace.removeListing. All of the new methods have been documented, as now linked in this post.