There seems to be a generous use of ClassMethods in ObjectScript code generally. I hope my own experiences aren't representative, but I bet they are. Forgive me for giving away the ending of this article, but in short: don't use them. Unless you can make a pretty convincing case that you have to, just never use them.1
What is a ClassMethod? In an ObjectScript class, you can define methods in two different ways: in a Method, you must instantiate an instance of the class to call the method, and in a ClassMethod, you can call the method without instantiating the class. Of course, in a ClassMethod, you don't have access to any properties of the object (because there's no object), but you can access globals (they are global, after all) and Parameters (which are class constants).