Jquery deferreds with pipe and when

http://joseoncode.com/2011/09/26/a-walkthrough-jquery-deferred-and-promise/
function getCustomerSSNById(customerId){
    var deferred = $.Deferred();
    setTimeout(function() {deferred.resolve({"ssn" : "111 44 9999"});}, 300);
    return deferred.pipe(function(p){
        return p.ssn;
    });
}

function getPersonAddressBySSN(ssn){
    var deferred = $.Deferred();
    console.log("ssn is " + ssn);
    setTimeout(function() {deferred.resolve({"address" : "123 blah st"});},1000);
    return deferred.pipe(function(p){
        return p.address;
    });
}

function getPersonAddressById(id){
    return getCustomerSSNById(id).pipe(getPersonAddressBySSN);
}


getPersonAddressById(123).done(function(a){
        alert("The address is " + a);
});

And using when

$.when(getCustomerSSNById(123), getPersonAddressBySSN("123 45 6789"))
    .done(function(person, address){
        alert("The name is " + person.ssn + " and the address is " + address);
    });