With ad networks falling out of favor with content sites, has the end finally arrived? Underscore Marketing's president reads the tea leaves.

For the last few months, many of the rep meetings we've been having here at the office have had a common theme. It seems that suddenly, brand-name content sites have decided that broad, high-reach ad networks aren't cool anymore. And, to varying degrees, they're changing the relationships between their sites and their network partners.

In many cases, they're scaling back the amount of inventory available to networks, or the number of networks they let sell into their sites. But in extreme cases, like that of Turner or ESPN, sites are pulling out of remnant networks altogether. I've heard Wenda Harris Millard's "Pork Bellies" quote more times than I can count.

"Ad networks cheapen the brand… Ad networks undercut our site's sales force… Ad networks are commoditizing digital advertising." It doesn't really matter how the dish is served up to media buyers. The underlying message comes through loud and clear. There will be fewer routes to ad inventory on premium sites.

Just about every media buyer is guilty of it. Buying around a sales force with network inventory is pretty easy -- why pay $30 CPMs on a content site when you can pay $5 through a network? (Okay, it's not exactly that easy, but it's close…) Content sites see how networks are undercutting them, and it's got to be frustrating to see the bigger networks outperforming content sites on unique reach in syndicated research all the time. So it makes sense that the networks that bite the hand that feeds them should find themselves in a bit of a pickle.

Still, ad networks serve a valuable purpose. A few of them, actually. And it makes me wonder if doing away with networks altogether should be the preferred approach of premium content sites.

If you head up sales for a content site with anything more than, say, a million unique visitors a month, the odds are against you that you can successfully sell out all of the ad inventory on your site in a given month. There are well over a thousand properties tracked by comScore that reach at least 1 million uniques a month. How many sellers can a buyer possibly meet with?

No, most content sites are between 30 and 60 percent unsold (perhaps more) before networks get a shot at inventory. Even if you've managed to sell all but 30 percent of your ad inventory, what's the best recipe for profitability at that point? Certainly it doesn't involve letting the inventory expire.

I've heard quite a few publishers say they want to gradually wean themselves off ad networks over time. I've also heard about working less with the big networks in the back of OMMA Magazine and more with content-specific and niche networks that take more care with publisher brands. Whatever the approach, it's clear that the wide-reaching ad networks are falling out of vogue.

This begs the question: Is it time for that ad network shakeout we've been predicting for the past couple years?

Perhaps. I think we're going to see a lot of announcements about content sites abandoning the big ad networks. I think we'll also see announcements about new relationships with smaller, niche networks or ones that are positioned to handle premium brands. Whatever the case, the networks in the crosshairs are the ones making the reach case to advertisers and agencies.

My prediction is that we're going to see the big networks slide a bit as more premium content sites jump on the anti-network bandwagon. It will take them a while to replace big sites by long-tailing it, particularly if the lost sites represent significant unique reach. 

We'll also see some new networks emerge that are specific to content niches, types of sites or particular demographics. These won't aim to become the next Advertising.com, but they will be content with building a reputation in their particular niche.

We'll also hear behind-the-scenes whispers about content sites very quietly crawling back to ad networks when they find out it will be close to impossible to sell out their sites.

So, I think there will be an ad network shakeout of sorts, but it will be focused on knocking the big boys down a peg or two and building up some of the niche players.

Tom Hespos is the president of Underscore Marketing and blogs at Hespos.com.