If you look here you will see an ad that is intended to be embedded in another site as an advertisement. Here is an example of where it is embedded.
The code responsible for displaying the ad in the web site is this:
<iframe src="http://ads.lockedonmedia.com/zones/204" frameBorder="0" scrolling="no" style="width: 160px; height: 600px;">
I like this approach in that, if the advertisement include dynamic content, such as "today's price," the content will be easily reflected in the hosting web page.
My question is this:
I realize that IFRAMEs present navigational issues, but is there a real impact on SEO and should SEO-sensitive developers avoid using it at all costs or are there circumstances where it can be used w/o harming your ranking?