Until a few months ago, and despite what each camp’s supporters might claim, opening an ad in a new window (target=”_blank”, target=”new”) or in the same window was more a matter of look and feel than a strategic choice, as the difference in conversion between the two methods was hardly noticeable.
Opening an ad in a new window was a way to differentiate advertising from content — navigation-wise — and not having visitors loose track of your site. On the other hand, using the same window looked like a “cleaner” and smoother way of navigation, especially catering to online surfers who prefer to use the “back” and “forward” buttons.
However, with the recent proliferation of toolbars — most particularly from Google, Yahoo & Alexa — , which all offer pop-up blockers, new windows will get irremediably blocked, which most of the time will result in loosing sales, as visitors might not know how to unblock ads — or just might not want to bother.
It is therefore recommended to open ads and affiliate links in the same windows, in order to avoid breaking conversions.