Facebook has developed a book swap feature for its Marketplace application called Marketplace Book Exchange that enables users to buy and sell books from and to each other. Books are identified by buyers and sellers by their ISBN numbers, and curiously it looks as though there is no way to view all of the books offered in a particular network.

On the one hand, this appears to be a smart move for Facebook, as college students are fed up with buying expensive textbooks from their college bookstores. The Social Graph certainly lends itself to buying and selling items from others within a localized market, such as a college campus.

However, Facebook is not the first to try helping college students find better deals online. There are several websites, such as Campus Books and eCampus, dedicated to this purpose. There are even two applications developed on the Facebook platform – Swap Roll Book Exchange and Campus Book Exchange – meant to help Facebook users find books and other items that others currently own and are willing to sell or trade.

While these Facebook applications have a combined total of less than a thousand users each, they may have experienced a surge of growth as students return to campus this Fall. Now that Facebook has developed its own application for book-swapping purposes, these independently developed applications don’t have a chance. Moral of the story for Facebook application developers: if the idea behind your application is any good, expect to see Facebook develop its own application to supplant yours. Don’t expect them to just sit on the sidelines and watch.

Thanks for the tip Noah.