The number of Facebook's UK users dropped by 600,000 in December,according to data by social media monitoring firm SocialBakers. Though representing a typical seasonal dip in use over the Christmas period, the UK was the only one of Facebook's 10 busiest territories that saw a seasonal fall, with user numbers dropping 1.86%. On SocialBakers' index the UK ranks as the world's sixth most active Facebook user base, with more than 33 million unique users in December.