It's only logical that, as the effectiveness, scale, and scope of behavioral targeting increase, so too will the number of dollars being spent on it.

"Unlike a few years ago, when very few people knew what behavioral targeting was, it's very clear to everyone now that it's the No. 1 monetization tool," AlmondNet's Shkedi says. Yet, according to Shkedi, companies are still spending a disproportionate amount of their budgets on paid search ads. "People spend approximately 5.2 percent of their time online on general search engines, such as Google, and only a third of their searches are commercially related," he says. "So it's 1.7 percent of their online time. Well, approximately 40 percent of the online advertising dollars are paid search ads -- fixed ads that are mainly placed on searchable pages."

Along these lines, ValueClick's Ardis believes behavioral targeting will eventually become a mainstay component in online campaigns. "Where, traditionally, it's been demographic targeting as your foundation, and then campaigns build off of that, I believe that, moving forward, behavioral will be the foundation," he says. "Because it's the richest, most productive kind of targeting there is."

Likewise, FetchBack's Little says dollars spent on retargeting consumers will soon no longer be optional. "In another two years, retargeting starts to become a line-item budget for marketers out there," says Little, arguing that marketers who fail to retarget consumers who've already expressed some sort of interest is akin to leaving money on the table. "Staying in front of them is hugely important because you've already made the investment. You've already paid the majority of the money to get them there. To not continue that investment to get them to convert is a waste."

As BT metrics improve and success starts to be measured in terms other than clicks and conversions, Datran's Knoll says the industry will start to see more ad dollars shift online. "That will allow the biggest advertisers, who spend the most money and currently spend it on TV and other mediums, to take their money off the sidelines and bring it online," he says. "I think that will ultimately allow the web to realize its potential."