A ton of publishers are using paid traffic sources to grow audiences.

http://www.outbrain.com/blog/automatic-yield-audience-development
http://uk.businessinsider.com/taboola-launches-backstage-monetization-analytics-product-2016-3?r=US&IR=T

It would be nice to use the advance reports section to add in paid traffic to show by source (Facebook, RevContent, etc) where profits or losses are happening by URL--or something like that. I don't want to use a tool that's entirely arbitrage because that could lead to a ton of crap traffic.