Multi Site Manager (MSM) enables you to easily manage multiple web sites that share common content. MSM lets you define relations between the sites so that content changes in one site are automatically replicated in other sites.
For example, web sites are often provided in multiple languages for international audiences. When the number of sites in the same language is low (three to five), a manual process for syncronizing content across sites is possible. However, as soon as the number of sites grows or when multiple languages are involved, it becomes more efficient to automate the process.