The document discusses communities within Alstom and how they benefit both the company and employees. It defines communities of practice and social networks, and explains how communities connect people, facilitate knowledge sharing, organizational development and training. Communities are different from other structures in that they focus on sharing knowledge and developing skills through collaboration rather than accomplishing tasks. The benefits of communities include access to knowledge, problem solving support, and idea sharing. Building a successful community requires defining its identity and roles, activities, resources, and launch. Interactions within communities are guided by members, leaders, and sponsors. Communities can strategically, operationally, and culturally impact the company when supported long-term.