In an earlier post, I talked about returnType and CFCs. Specifically, I talked about how if you want to return a CFC from a CFC method, you simply use the name of the CFC in return type. What if you wanted to return a CFC, but you didn't care what CFC you returned? All CFCs extend one base component. You can see it in the hierarchy when you display a CFC:

WEB-INF.cftags.component

If you set returnType equal to this value, then you can return an instance of any CFC from your method.