An object, that moves through a virtual world, generates position update events. To display a fluid movement on other clients a minimum of about 10 events per second is required. Clients, which are connected to a world with hundreds or thousands other players, can neither receive nor process all these events due to the limit of resources. Managing the interest is the key to success: each client should only get what he needs (what he sees).
A common solution is region-based interest management: The world is divided into multiple regions and clients receive the events that originate from regions within their view distance only.