My best guess is that a lot of the companies use other companies for "backup" inventory. So when they run out of their own surveys, they start routing people to the other companies so that they can still make some money. I hate that for US because it complicates things. I try to only work with companies now that have their OWN inventory and they always tell me that they do. But I think they DON'T tell me that this is what will happen when they run out of inventory.