The ability for us as an agency, who have been working in this space since 2010-11 (and before) is that we can now do more than just deal/manage inventory - our clients are able to see where it's being sold & what they're getting out of each publisher! This has allowed them greater insight into how well or not so much certain partners perform compared to others which allows better decision making about future partnerships / deals etc.. Nothing really but I guess if you were looking at other products then maybe there would be something else? It works very effectively across all sizes from small local sites through large global players like Google.