An article published in ClickZ today shows that ads are clicked on the most during the first 5 pages of a visit.   There’s a 40% drop off between ads being clicked on on the second page of a visit than the first page, and so on.

"The first thing we saw was from the first page to the second, there’s a 40 percent drop-off," said Tribal Fusion VP of strategic marketing Alistair Goodman. "The curve held pretty constant across all the sites we were looking at."

…..Tribal’s research reinforces findings from aQuantive’s Atlas Institute. Though clicks dropped off 40 percent from the first page view to the second, in Tribal’s study, page views four through 13 maintain a consistent level of clicks. The largest drop takes place after 20 page views.

"…..Tribal’s takeaway is that clients should be selective about inventory. "All impressions are certainly not created equal," said Goodman. "We tell our clients to beware of remnant inventory. The later your message is seen, the less likely a user is to respond."

One thing that I’d like to know - does the study also take in account that visitors leave the site after a couple of pages, for the most part, and therefore - they may not be as many clicks on ads because there’ s less visitors and less traffic?

To me, unless you can show the same amount of traffic (the same exact traffic) went from page 1 to page 2 (there was not drop off of visitors) but the same traffic on page 2 clicked on 40% less ads than page 1…. then you’ve got something.

But what you have in this study just tells you some inventory is better than others - not why it’s better.