Amazon.com has developed an application that allows Facebook members to write book reviews, share them with their Facebook friends, and buy them from Amazon.
European ticketing exchange, Viagogo, has developed an application that allows members to buy and sell their tickets to live events.
Facebook has attracted the interest of new media giants such as Yahoo, but it has become increasingly clear that its founder, Harvard drop-out Mark Zuckerberg, is not keen to sell, even with a reported valuation of $1bn.
Zuckerberg described the site's new strategy as a move away from running social networks as "closed platforms". Speaking at an event held yesterday, he showed software developers how to use his company's development platform to build their own services to run on the site.
He said: "Facebook Platform creates an ecosystem for developers to build applications that deeply integrate into Facebook and use its social graph ... we're working together to create a better utility for millions of people."
Facebook will not take any share of the revenue generated from transactions between users and third parties, according to Zuckerberg.