Some of the networks leave branding links and tracer codes identfying the network. In the case of this particular network, I'm seeing over 7m incidents of "Enhanced by xyz " in the Google search results coming from the alt attributes and related code.
If other sites put links back to your content in a snippet of your aggregated content, on any scale and it's identified as a network, potentially medium to low quality I just wonder if it might tip Google to discount, neutralize or even penalize both publishers and advertisers.
Then there's the issue of the content surrounding the links being considered authority.
Also, IMO , the model is really selling links in a round about sort of way isn't it? I mean if you're paying for impressions it equals a sale if someone links back to you as a percentage of impressions. I mean I know folks will argue that it isn't, but it might be interpreted otherwise by Google - and they are the folks one has to second guess as to what is acceptable or not.
It looks less crude than some of the other networks that bit the dust 3-5 years ago, and more sophisticated in intent than existing ones, but I just wonder if these types of setups pass the webmaster guidelines test at Google.