Let's try to be constructive here
We give the possibiliy to buy CPC or CPM traffic. It's up to the media buyer. A simple strategy we suggest is to buy CPC traffic with RON (run of network) campaigns and consider it as a funnel. By using a basic tracking technology and basic analytical skills, media buyers can quickly block the sources that do not convert and focus on traffic sources that are profitable. You can actually see every single source of traffic sending traffic to your landing page. So no need to be a genious to make it works. You need to spend time to analyze stats and invest some budget at the beginning to get enough data (unfortunately, profits don't fall off the trees...).
With no experience in media buying, CPM can be tricky to start with because you may "burn" some budget if you don't know how to fine tune the targeting and cappings of your campaign. That's why we created a marketplace of Premium ad spots. There, we know that both the volume of traffic and the conversion ratios are good. It helps media buyers to save time and buy directly on the best sources of traffic we have available. There, we suggest to use CPM in order to grab a decent volume of traffic. But once again, if you don't use any tracking devices, you'll lose money and complain on GFY ;)
On serious ad networks (there are a few you can count on), you are given all the tools to follow your conversions and ROI in real time (pixel tracking or API). You are also given all the statistics updated in real time as well as very precise targeting options. These companies were often created many years ago and filled with experts that are able to give you the right tips to start buying traffic seriously.
I think it's also very important to make a difference between the real ad networks using a strong technology and working directly with their own webmasters and advertisers VS the ad networks that are profiting of the trend of traffic brokering and that are re-reselling shit remnant traffic bought from other brokers and other ad networks.