If your opponent played well, you may want to applaude him. The player will receive a corresponding message in his chat window and the server will keep count of how many applauses he has received.

 

You can check that in the player's personal info.

 

Click the Applause Button:

 

 

If you kibitz a game, you can send applause to one or both players.There is one button for the white player and one for black.

You can also applaude a player in the players list by right-clicking and using Edit – Send applaus. There is a restricted number of applauses you can send per day.