Actually, in the way Priceless and Worthless are used price and worth don't mean the same thing. Having worth, in this case, indicates that whatever the subject is it has value to it, while not being specific to what that value is. Price, on the other hand, means that the value of that object is specific. So, for instance:
Object A is desirable, therefor it has worth. After finding out what that object is worth, a price is set for Object A.
Object B is desirable, and therefor has worth. However, it is so desirable that one cannot find something of equal worth to set a price for Object B and cannot set a price. Therefor, the object is priceless but not worthless.
Object C is not desirable, and therefor has no worth. Since it has no worth, it is worthless. Technically, this makes it priceless as well, however one could say that the price is $0.00, making it not priceless but still worthless.
After two years of quality posting and abiding by the rules of the forum, I was asked to be a community moderator when a slot on the team opened up. Simple as that. Openings are very rare, however.
It appears the "when" is 6/12/2014, the "how" is by typing something and pressing "post", and the where would be a secret. Somewhere on the site you don't have access to.