So what do I mean by this? There are so many ways to slice and dice the ad network landscape that it's almost mind numbing. Because there are new entries into the space everyday, it makes it almost impossible to figure out the differences and why they matter.

Representation, ad network or a hybrid?
So the main way of slicing the ad network space is to think about it in terms of what kind of business model they run.

Representation firms
There are the rep firms that merely represent the sites and sell inventory, such as Winstar and Gorilla Nation. They will sometimes have an exclusive arrangement to do this as the only seller of the inventory -- so the site doesn’t sell it at all -- or possibly as the only outside source to sell that inventory. And sometimes they will share the responsibility of selling the inventory with other rep firms. But in most cases, they will either sell the inventory exclusively or share that job only with the site.

Ad networks
These typically fall into the other two categories: pure and hybrid networks. They might represent some sites on a single site basis, but they also have the ability to target your ads in custom channels or throughout their whole network. It gets a little challenging to know where each network falls, so you must be very specific when talking to the networks as to what your options are and how they operate.

So now we know the basic categories networks can fall into. How do those categories further break down in terms of differentiating factors. Let’s start with pricing.