Knowledge management as a conscious practice is so young, there're no successful models. Hansen et al. studies the knowledge management practices of companies in several industries. They started by looking at consulting firms. Knowledge is the core asset of consulting, so they were among the first business using knowledge management. Overall they use two different types of strategy: first the codification strategy: knowledge is codified and they have put it in a database so everyone can use it. The second strategy says that knowledge is tied to a person and they share it through personal contact, in other words personalization strategy, and the purpose is the communication of knowledge. Hansen et al. believe the choice between these two is the central choice to knowledge management.