One of the advantages of this model for a publisher is fast and fixed payments. Besides, the profit of the publisher working on CPO is higher than that in the ecommerce. However, it is more challenging to work on this model, as it involves searching for sources of 100% target traffic. If the webmaster is unable to find the source of traffic, he has to bear the advertising costs and risks. Consequently, there is a real chance that the webmaster will spend his own money on advertising and not get paid at all. Oops!