Overview
Using the @instance tag will mark a symbol as an instance member of its parent symbol. This means it can be referred to by "Parent#Child".
Using @instance will override a doclet's default scope (unless it is in the global scope, in which case it will remain global).
Examples
The following example is a longhand way of writing "@function MyNamespace#myFunction":
/** @namespace MyNamespace */
/**
 * myFunction is now MyNamespace#myFunction.
 * @function myFunction
 * @memberof MyNamespace
 * @instance
 */
More usefully, you can use the @instance tag to override the scope that JSDoc infers. For example, you can indicate that a static member is used as an instance member:
/** @namespace */
var BaseObject = {
    /**
     * foo is now BaseObject#foo rather than BaseObject.foo.
     * @instance
     */
    foo: null
};
/** Generates BaseObject instances. */
function fooFactory(fooValue) {
	var props = { foo: fooValue };
	return Object.create(BaseObject, props);
}