Sparse Mode is a multicast routing technique used in computer networks to efficiently manage data transmission. It allows routers to only maintain multicast group memberships for active participants, reducing unnecessary bandwidth usage. This is particularly useful in large networks where not all devices need to receive the same data simultaneously. In Sparse Mode, routers use a protocol called Protocol Independent Multicast (PIM) to establish a shared tree for data distribution. This method minimizes the amount of multicast traffic on the network, ensuring that only those devices that have expressed interest in receiving specific data streams are included in the transmission process.