With the release of the Gateway system in Brood War, two players can play at the same time, as long as they are on different gateways, though they cannot play in the same game, chat with each other, etc. Every Blizzard game since StarCraft has required a unique, valid CD key to connect to (excluding StarCraft: Brood War). In addition, only one person can be connected to service using a specific CD key at a time. A StarCraft CD key is a generated 13-digit number that could either be muted (unable to chat), voided (restricted to channel 'The Void'), banned (disabled usage), or usually working (no restrictions). With StarCraft, only those players who had a valid CD key were allowed onto the service. This allowed people who pirated the game to play on. Under Diablo, would allow anyone who had a copy of the game to connect to the service. StarCraft also brought with it a new copyright protection scheme using CD keys. This was especially evident in South Korea where StarCraft became a runaway hit and concurrent player counts on would often be many times what they were in the United States. Concurrent player counts and games played reached the tens of thousands. grew even larger after the release of the expansion pack StarCraft: Brood War.
Features such as ladder ranking and game filters were added to the service.
With the release of StarCraft in 1998, usage of the service increased significantly in comparison to Blizzard's previous games.
