Spending money online is about to become more social and probably less private. Online buying sites have long known your preferences, but how many of your Facebook friends know what you buy where? And how much do the suppliers your friends buy from know about you? Answers to these questions will coalesce as Facebook users try out new apps that allow them to buy pretty much anything on the social platform.

Until June last year, Facebook users could use ‘credits’ to pay for virtual goods such as games. From July, developers could build third-party apps, letting users spend their real local currency.