Very simple topic subscription.

example.js

var a = topic();

a.add(function(){
  console.log('a', arguments);  
});

a.fire('message for a'); // should be "a", ["message for a"]

// named topic
var b = topic('b');

b.add(function(){
  console.log('b', arguments);
});

b.fire('message for b'); // should be "b", ["message for b"]

var c = topic('b');

console.log('b and c are the same', b === c);

c.fire('message for c'); // should be "b", ["message for c"]

topic.js

var topic = (function($){
  var t = {};

  return function(name) {
    return t[name] = t[name] || $.Callbacks();
  }

}(jQuery));