Actually the whole world is full of Krsna's singing, but it is appreciated in different ways by different kinds of living entities. This is confirmed in the Bhagavad-gita: ye yatha mam prapadyante tams tathaiva bhajamy aham [Bg. 4.11]. Krsna is dancing, and every living entity is also dancing, but there is a difference between the dancing in the spiritual world and that in the material world. This is expressed by the author of the Caitanya-caritamrta, who says that the master dancer is Krsna and everyone else is His servant. Everyone is trying to imitate Krsna's dancing. Those who are actually in Krsna consciousness respond rightly to the dancing of Krsna: they do not try to dance independently. But those in the material world try to imitate Krsna as the Supreme Personality of Godhead. The living entities are dancing under the direction of Krsna's maya and are thinking that they are equal to Krsna. But this is not a fact. In Krsna consciousness, this misconception is absent, for a person in Krsna consciousness knows that Krsna is the supreme master and everyone else is His servant. One has to dance to please Krsna, not to imitate or attempt to become equal to the Supreme Personality of Godhead. The gopis wanted to please Krsna, and therefore as Krsna sang, they responded and encouraged Him by saying "Well done! Well done!" Sometimes they presented beautiful music for His pleasure, and He responded by praising their singing.

From Srila Prabhupada's Krsna book, ch. 33: Description of the Rasa Dance