Here is everything you need.
Like i said already in the comments you can't sort an object.. but you can put it into an array and display the results.
var array=[],obj={
caffeineoverdose:'2517',
workhardplayhard:'761277',
familia:'4633452'
};
for(a in obj){
array.push([a,obj[a]])
}
array.sort(function(a,b){return a[1] - b[1]});
array.reverse();
DEMO
http://jsfiddle.net/GB23m/1/