The user list panel shows the list of currently online users, and their rating for each rating type. You can challenge a user to a game by clicking on their challenge button. Other user specific actions, such as friend requests or bringing up the user's stats page can be accessed by clicking on their username.

The user list can be filtered by username or rating range. To filter by rating range, you will need to select the rating type the range applies to. The username filter is a case sensitive substring search, so for example "ern" would not match "Ernest", but "Ern" would.