This is the basic dilemma of all online publishers. Do you devalue your brand by allowing advertisers to pay a discounted price for your ad space, or do you maximize your sell-through rate by allowing ad networks to sell your otherwise unsold inventory at reduced rates?
The trick is to be vigilant in not allowing your target advertisers to get on your site through the networks. This is easier for highly trafficked sites with a desirable demographic. When I worked at wsj.com, the ad sales team never strayed from rate card. But they didn't need to. They knew their clients would pay a premium to be on The Wall Street Journal.
But what about less popular sites, like The Christian Science Monitor's csmonitor.com? (one of my favorite sites - I worked there for 6 years.) Their revenue is comprised mainly of print subscription revenue, although they recently announced a switch to a mainly digital model. With low advertiser demand, they may have no choice but to offer their inventory at lower rates and try to sell as much inventory as possible through the ad networks.
The bottom line is this: if your content isn't differentiated enough, you won't deliver a targeted audience or garner a premium CPM. Your lower-than-ideal sell-through rates will force you to surrender your inventory to the ad networks. There's no shame in this. Everyone does it, and it's part of any smart revenue strategy. But before allocating a huge percentage of your inventory to the ad networks, make sure you've exhausted all possible channels through topic-based and behavioral targeting. And by all means make sure you block your target advertisers from appearing on your site through the networks.
