How is server rank calculated?

Server ranks are calculated one of two ways:

1. If the game provides a way to retrieve the player list, we calculate rank based on the average number of hours played by players on the server over the preceding 7 days. This is calculated daily.
2. If the game does not provide a way to obtain the player list, we calculate rank based on the average player count over the preceding 7 days. This is also calculated daily.

In short, rank is based on the popularity of the server. The more players and playtime on a server, the higher its rank.