Big Data age puts privacy in question as information becomes currency. This month, the US chain Walmart bought the startup Social Calendar, one of the most popular calendar apps on Facebook, which lets users record special events, birthdays and anniversaries.
More than 15 million registered users have posted over 110m personal notifications, and users receive email reminders totalling over 10m a month. Of course, when a Social Calendar user listed a friend's birthday or details of a holiday to Malaga, she or he probably had no idea the information would end up in the hands of a US supermarket.
But now it will be cross-referenced with Walmart's own data, plus any other databases that are available, to generate a compelling profile of individual Social Calendar users and their non-Social Calendar-using friends.