Enlarge (credit: Getty Images) Still smarting from last month's dump of phone numbers belonging to 500 million Facebook users, the social media giant has a new privacy crisis to contend with: a tool that, on a mass scale, links the Facebook accounts associated with email addresses, even when users choose settings to keep them from being public. A video circulating on Tuesday showed a researcher demonstrating a tool named Facebook Email Search v1.0, which he said could link Facebook accounts to as many as 5 million email addresses per day.