Whenever a game is shared between two or more people over the internet, it is usually hosted on a server. The server will collect information from all parties, send information back, and generally allow you all to play together with minimal delay. Usually, when a game is released with online play, the developers will dedicate official servers for players to use and play on. There’s often also the option to host your own, but for most popular games, especially on console, official servers are the way to go.
The largest games will often dedicate countless servers, all prepared for the heavy traffic that comes with popularity, but what happens when the playerbase dwindles? Servers aren’t free, and for game companies, running official servers is an investment they hope pays out in continued sales of their games and new players. When new players don’t come, though, it’s often best to reduce the load. If old players move onto a new game and even more servers go unused, those are closed as well. And if the trend continues, you’ll eventually end up with a dead game, where no matter how much you try, there simply won’t be any servers to connect to.
This has happened to many games in the past, and continues to happen to modern games, with countless posts online asking the ever so important question “are people still playing.” No one wants to buy an online game only to find out the entire population caps out at 200 players on the weekend. Which is why so many games try so hard to find a fountain of youth that will keep them relevant for time to come. Whether by mastering a niche and offering expansions (like World of Warcraft) or maintaining a competitive scene that keeps the game in everyone’s radar (Counter Strike: Global Offensive, League of Legends, DOTA 2), keeping people playing years after release is a goal for all creators who understand that playerbases are the lifeblood of online gaming.