I wrote earlier about my philosophy on classifieds: keep the number of them low to focus your advertising dollars so that you will show up higher on the search results list. I'd like to amend that idea here, by introducing a new twist.
While the original concept is still valid, it assumed there were only a fixed set of keywords that people would use to search for your products. As my inventory of for-sale products increases, I now find I have some items that don't really fit with my main classified ad. In other words, people would likely use different keywords to find those products.
So, I realized that you could feasibly have more than one classified ad – as long as they each focus on a different set of keywords. Also, they each probably have different payments to get onto that all-important first or second search results page for the keywords they are designed around. In this way I believe I have optimized my classifieds by spending the least amount to get the maximum results.
And it seems to work! I am getting somewhat more traffic lately.