In this video [via Kottke], John Green explains why competitive players are suddenly getting much better at Tetris despite the number of players being much smaller than in its heydey: "a group of enthusiasts built spaces both online and off that allowed people to connect with each other over what is usually a very solitary hobby and because small groups of deeply passionate people can often be more productive than large groups of casually interested people."
The improvements apply to a specific implementation of Tetris (8-bit Nintendo) and reflect deep awareness of the technical environment.