Search Engine Marketing is now all about conversion rates, if you can increase that conversion rate by a small percentage then you are making progress. If the one thing SES conference in NYC wanted to drive home was that driving traffic to your site can be worthless, if you do not drive quality and actionable traffic. That being said...
I was visiting one of my daily sites VersionTracker (yes I use a Mac) and I saw an eye catching banner at the top. So I clicked, not because it was eye catching, but because I was interested in the product. It took me to this page. Find it yet? The "Add to Cart" button? Scroll down, yea all the way, scroll down until you can't scroll anymore. There it is, on the bottom right. Now, what was I adding to my cart? Scroll back up, there it is - ok now how do I add it to my cart? See my point?
You need to convert this sale right away! I am not going to buy it now.
FYI - I have a huge monitor with a lot of screen real-estate.