Banks today face greater risks from bad word-of-mouth on social media networks than they do from regulation and other higher-profile threats, says prominent global banking consultant Brett King.King, an expatriate Australian and author of Bank 2.0, said in an interview with Banking Day that banks continue to underplay the effects of social media networks such as Facebook and Twitter."To some extent, the biggest risk that banks face today isn't... regulation or things like that - it's a reputational risk from a one-time event on social media," he said."Customers who are unhappy tend to talk a lot louder than customers who are happy.  So, if you've got a poor service position, then social media is bad for you, because you're going to get a lot of exposure."King argued that the reach of social media now meant that "having a head of social media is more important than having a head of call centre." When customers had a bad bank branch experience two decades ago, they would ring the call centre, said King. "Today, they do exactly the same, but… they pick up the Facebook phone or the Twitter phone. They conference-in 20,000 of their closest friends and family and they have the same discussion, ranting and raving down the phone line [about] how terrible the bank is and how terrible an experience they've had."Banks also systematically over-rate the influence of their branches, King believes. "Ten years ago, customers were coming into the branch once or twice a month, now they're coming into the branch twice a year…  Our behaviour has completely changed over the last 10 years, and yet banks will still tell you, 'Oh no, the customers love coming into the branch'."Australian banks' enthusiasm for opening extra branches over the past decade, he said, had been a traditional and instinctive reaction to rising revenues.