Enterprise collaboration software is often criticized for over promising and under delivering on business value. Yammer, on the other hand, is having the opposite effect within many leading organizations, frequently exceeding expectations in unanticipated ways. This is largely due to the fact that, unlike other tools, Yammer is voluntarily adopted by employees. When colleagues willingly share knowledge and information across organizational and geographic silos, it cultivates an environment ripe for collaboration, innovation and serendipitous connections.