Clicking on the button allows users to buy a promoted item without leaving Facebook's site, and to save the payment info they provide for future purchases. The feature is being tested out with a handful of U.S. SMBs. Facebook isn't charging a transaction fee for now, but is open to doing so down the line.
While Facebook does plenty of business with e-commerce advertisers - Nanigans' Q2 numbers drive this home - users have until now had to leave Facebook to finish a transaction (virtual goods purchases excepted). If on-site purchasing improves conversion rates, Facebook can benefit either directly (by charging a fee) or indirectly (by charging higher ad prices).
Separately, Facebook has rolled out Mentions, a new app meant to help verified public figures interact better with their Facebook fans.
Facebook and Twitter have been battling for celebrity support for years. Each platform has its strengths: Twitter has been better at fostering conversations with fans, and Facebook has been better at getting out celebrity messages that require more than 140 characters.
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