Monolith Productions' now-dead MMO The Matrix Online had fewer than 500 active users prior to shutting down, said Linda "Brasse" Carlson, director of global community relations at Sony Online Entertainment during a presentation at GDC Europe 2013.
During the presentation Carlson highlighted the unfortunate necessity of shutting down games in order to maintain the studio and its economy, often regardless of whether a small but tight-knit community is still present.
"The breaking point where cost of maintenance just to keep the game up was ridiculous," she said, referring to SOE's attempt to continue the then four-year-old game. "Sometimes you just have to shut these games down."
The Matrix Online officially launched to North America and Europe in 2005 before being shut down by Sony Online Entertainment in 2009 due to a low number of subscribers.
Carlson would go on to emphasize the importance of communication between developers and community through community management, along with the failures of communication throughout the development of Star Wars: Galaxies. You can check that out here.