The study goes on to indicate that 9 out of 10 people in the study who eventually made a buying decision were reached by the ad in at least one other location (see chart below). We know that repetition is important in advertising. This article helps us know how much our repetitive advertising helps us.
One important note to make is that repetition is not best in all advertising applications. Plus, we should not simply advertise in various locations, but targeted locations where the same consumer visits. That requires a better knowledge of who is coming to our sites and where they shop.
Although, that could be a topic unto itself, I wanted to give you a couple recommendations if you're interested in learning more. Hitwise is a company that provides this data most accurately. But it comes at a steep price. There are some web analytic tools you can buy for your site that attempt to find out this information as well. Both WebTrends and Omniture provide this information if integrated appropriately. They can also be pricy, but if buying the WebTrends software (not the company's hosted solution) the use of the software can be depreciated over time. However, the best reliable option I quickly found for almost any size business is Google’s latest Google Analytics package. It’s totally free unlike the others, but Google then gains knowledge of your site’s performance and visitor behavior. Typically, that won’t be a problem. However, it’s certainly important to note.
The study is summarized pretty well by eMarketer. You can view this article until around July 4.