Getting good-targeted traffic is a good way to make better sales. If you sale shoes and you get a lot of traffic for people searching for mortgage loans then you may not get very many sales. Also just spending all your time on the terms shoes or shoes for sale will not get you that much traffic as well. Try bidding high for a general term like shoes on Overture or Adwords and turn broad match on. You will notice in your logs that more than 50% of your traffic will come from terms that were typed in only once in a 30-day period. General terms bring lots of traffic but it is not targeted very well. A site should go after thousands of terms. You can use tools like word tracker to get thousands of terms. You can then start optimizing tons of pages for those terms. You will see a large increase in traffic and sales. Your conversion rate will skyrocket as well. Use basic SEO on page rules on a PR5 or higher site and you will be happy.