The US military is developing software that will let it secretly manipulate social media sites by using fake online personas to influence internet conversations and spread pro-American propaganda. A Californian corporation has been awarded a contract with United States Central Command (Centcom), which oversees US armed operations in the Middle East and Central Asia, to develop what is described as an online persona management service" that will allow one US serviceman or woman to control up to 10 separate identities based all over the world. Critics are likely to complain that it will allow the US military to create a false consensus in online conversations, crowd out unwelcome opinions and smother commentaries or reports that do not correspond with its own objectives. The discovery that the US military is developing false online personalities - known to users of social media as "sock puppets" - could also encourage other governments, private companies and non-government organisations to do the same. Once developed, the software could allow US service personnel, working around the clock in one location, to respond to emerging online conversations with any number of co-ordinated messages, blogposts, chatroom posts and other interventions.