Undoubtedly, behavioral marketing has become a staple in many a savvy company’s online marketing plans. The question becomes whether it is being used properly to achieve higher ROI, or simply increases ad costs with unclear or lackluster results.

The projected US ad spend alone for 2010 is 27 billion, and 61 billion globally, in US dollars. That is a growth of 16% from 2009. Also note, less than half is from paid search ads, indicating a growing success with banner ads and similar mediums for some businesses.

The vast majority of those ads now claim some form of behavioral targeting. Marketers embrace the concept, question is: does it just increase costs, or is it really increasing ROI in your campaigns? A very cost effective form of behavioral advertising that is becoming increasingly popular is re-targeting.

It is so profitable because re-targeting serves ads to those who have specifically already seen your website and/or performed a specific action, but not purchased. Lets face it, what percentage of your visitors buy on their first visit? The more that someone sees your product, the more likely it is that they will buy it. Traditional wisdom has told us that a prospect needs to see your product 7 times before making a buying decision.

You can regain many of these visitors as future customers, as their likely hood to buy is much higher than cold prospects. Internet consumers investigate before they make a purchase. Even if they want and like your product, they are likely to think about it, shop around, or investigate the product before you can close the sale.

By developing a re-targeting strategy you can expose that same consumer or business to specific ads designed for previous visitors, as they surf the web. Also, for products with a longer purchase cycle, re-targeting is effect because it leverages sequential advertising to reinforce your message, as the consumer goes through the process prior to completing a purchase.

You can build a large base of potential buyers to retarget, by combining re-targeting with traffic-driving solutions. For example, if you run a search campaign, re-targeting would be an excellent complementary solution to drive sales, for those that visited your site, but did not make a buying decision.

A growing number of ad networks support re-targeting as its power has become more apparent. Ad networks can make re-targeting quite effective, because they enable you to retarget visitors of countless sites across the net, rather than just one. You can also provide a custom message depending on the action the prospect took on your site, such as cart abandonment.

Re-targeted ads can be extremely successful in comparison with the an average online ad campaign targeted demographically. One study showed 10 times the number of sales conversions, and 21 times the number of info requests over an array of products.

With a lot of noise online about behavioral targeting of ads, re-targeting is one method that can clearly drive a lot of sales through your site, and improve your bottom line.