3. Ads get a halo effect from the websites on which they appear.

But wait -- doesn't La Quinta worry about the sites on which those networked ads might show up? Not at all.

"The way networks are targeting, they target where you audience is," Watson says. "Sometimes people underestimate the power of being where their audience is because they're overly concerned about their brand integrity. We’ve completely opened the floodgates to pretty much anyone who responds well to our ads."

That's a smart strategy, says Greg Koerner, a Yahoo alum who's now chief revenue officer for MediaBank, a provider of technology and analytics to the advertising industry. "My belief is that the industry should be selling and buying audiences and not inventory," he says. In other words, TravelAndLeisure.com may have the luxe look, but if more customers use Kayak.com, just do the math. This emphasis on inventory over advertising is a hangover from traditional media, Koerner says.

4. Post-impression attribution has matured.

In the past, whichever ad got a click got credit for all the action. One of the newest sciences in analytics is post-impression attribution -- the idea that you can chart the influence of each piece of media in a campaign to determine its contribution to the desired action or awareness. Although it's much better than examining entrails, this science is far from mature, according to media planners.

"My experience has been that the attribution models of even the most sophisticated ad servers can only take in a handful of feeds, and they struggle with de-duping actions appropriately," says Matt Hinson, VP of strategy and innovation for Mullen. Hinson's firm tries to combat this by building out data marts that can serve as a double count for both attribution modeling and general media impressions, in order to get a better feel for which campaign is actually performing.

Jeff Ratner, managing partner and North American director of interactive media at Mindshare, agrees. "I don't know if anyone has cracked the code, but it's critical," he says. "No medium exists in a vacuum." For example, search gets credit for plenty of clicks but, as Ratner points out, people often search for something because they're already aware of it. In other words, when it comes to post-impression attribution, Ratner says, "It's still not a heck of a lot different than where we were in traditional media."