Resource Description Format? Oh no, it's a Framework.

http://www.w3.org/RDF/

The declaration of the variable 'y' in the example is missing its keyword 'var' and will unintentionally create a globally scoped variable.
Should be:
var x = 2;
function test(){
var y;
y = x + 3; // could also place the var statement inline with assignment operator
}
console.log(x); // prints 2 to the JS console
console.log(typeof y); // prints 'undefined' to the JS console

The prototype inheritance pattern doesn't allow for true multiple inheritance (like what C++ has). However, you can fake it by munging functions from multiple classes into your class' prototype effectively providing the functionality of multiple inheritance in simple cases.

meaning that third parties can implement their own interface to Yahoo! mail.

http://developer.yahoo.com/mail/

This may be what Fairpoint is doing to give users access through their branded portal. These same APIs mean that any user can implement their own non-Fairpoint approved access mechanism for their webmail.

It may not be a solution for all users, but at least yahoo's opened up enough that there are options available in the case of abusive network access providers.