Facebook lost nearly 6m users in the US last month, according to figures from Inside Facebook, sparking fresh concern that the social network’s growth is slowing. Total monthly active users on the site still grew by 1.7 per cent between the beginning of May and early June, taking its total to 687m, according to Inside Facebook, part of the Inside Network, which provides news and analytics tools for social media, virtual goods and mobile apps.But in the US there was a drop for the first time in a year, from 155.2m to 149.4m during the month of May. Canada also...