Strong usage and a well-developed ad industry make Western Europe Facebook’s strongest outside North America. Ad targeting products such as Custom Audiences are overwhelmingly popular. However, privacy concerns and the potential for additional government regulation could derail revenue growth, according to a new eMarketer report.
http://www.emarketer.com/Article/Whats-State-of-Facebook-Advertising-Western-Europe/1012635?ecid=NL1002