What is spy island on Poptropica?

Spy Island was the 6th island of Poptropica, and was added to the site in 2008.

The object of the quest is to rescue three kidnapped spies, then use their information to stop the plans of the B.A.D. (Bald and Dangerous) villains, who are building their wig and toupee business by using a laser satellite to zap the hair of the island's residents.

(see related question)