Think about the top sites - Google, eBay, Yahoo - they continue to be popular because they allow users to do a deep dive into the tail. As search engine activity has grown, we've seen more traffic entering sites through deep linking - often times bypassing the home page altogether in favor of directly linking to the deeper, niche content. ContextWeb illustrates this point with a great Long Tail-esque curve for TheStreet.com (or, as ContextWeb describes it, the Passion Tail):

While the Home Page continues to get a high number of visits (like the broad-reach portals), we're seeing more people going directly to specific sections of the site for niche content (like sites in the tail).

Networks to the Rescue 

In an effort to maintain share and continously aggregate audiences, the portals have shelled out enormous sums of money to acquire ad networks: Yahoo! bought Right Media and Blue Lithium; Google acquired DoubleClick; Microsoft picked up aQuantive; and AOL brought together Tacoda and Advertising.com to form PlatformA. And just last week we saw rumors of an $800 million asking price for Tribal Fusion.

But it's not just the portals rushing into this space. Branded sites like MarthaStewart.com and Forbes.com have created extended vertical networks (Martha's Circle and the Business and Finance Blog Network, respectively). There are vertical networks like Travel Ad Network and Burst Family Traveler who aggregate the best of category-specific tail sites, making it easier to buy innventory across them. And traffic data suggests that these niche sites in aggregate will outrank even the better-known category sites:

The opportunities for advertisers are seemingly endless. There are blog aggregators like Chitika and Technorati; profile-based data targeting networks like 33across and Lookery; ISP data targeting networks like Front Porch and Phorm; contextual networks like ContextWeb; and many, many more. There's an uprecedented number of partnerships, alliances, co-opetition, and frenemies.  Microsoft owns AvenueA, which buys media from DrivePM, which is also owned by Microsoft (so, Microsoft is buying media from itself). Google is selling print and radio ads. SpotRunner is selling search inventory. Daunting but exhilerating, indeed.

While the options can be overwhelming, the truth is that ad networks can help marketers and their agencies plan and buy brand-safe media (meaning, placements on quality sites) across niche sites in a manner that provides both scale and control. In this way, ad networks help planners manage highly fragmented inventory with one buy and still reach a high volume, incredibly targeted audience.

The downside of networks? Often times, inventory from top tier sites and/or premium placements is not available (as inside sales reps prefer to sell that themselves), and the dynamic nature of the network buying process may be antithetical to planning engagement that require long lead times.

In some cases networks may be better suited to direct response programs, while brand campaigns still warrant publisher-level negotiations. But they can certainly be a fantastic way to round out your buy, and tools like Compete's Behavior Match can help identify the deep-level pages that will make the most sense for your particular campaign.

For those interested in reading more, there is a good Mediapost article on vertical networks (including what to look for when selecting them), and ContextWeb has made their presentation available on their blog (plus pictures from the event on Flickr). And of course your fearless Contact Planning team here at PARTNERS+simons is always eager to discuss these things - give us a call!