Search terms: You can find out the specific terms people are using to find your site, which will help you decide what the most popular topics for your readers are. However, Google searches are increasingly not providing the specific search terms that they used to, going with “not provided” instead, so this ability may decrease in the future (at least with the Google search engine).
But your money could also be spent on advertising your product to a community – not a random set of people For example, John Lee Dumas runs a podcast called Entrepreneur on Fire. If you have a great product that will make an entrepreneur’s life easy, you can hit him up there. His episodes cover all things entrepreneurial and he boasts a loyal audience. His September listens totaled more than 1 million. John even recently published a useful blog post about podcast sponsorships.