1. A method comprising: creating connections to multiple applications, each application having multiple entities; determining relationships between said entities within a single application and between entities across multiple applications; associating a tag with a selected one of said entities in a first one of said multiple applications; identifying entities in other applications besides said first application that are related to said selected entity, based on said determined relationships; and propagating said tag across multiple applications by associating said tag with said identified entities in said other applications.