Robert Scoble calls out the Google AdWords Keyword Tool and why it’s important:
What does this tool do? It helps you see the searches that people are actually doing on Google. Let’s say you had a quilting store. Do you really know what searches people are actually doing to find information about quilting? If you haven’t used this tool, no, you don’t.
This tool also is important to figure out how many people are searching for a particular topic. This helps you test your assumptions of how many people are really searching for something. This will help you choose your title tags, and, even, your content.
I look forward to checking this out and seeing what it means for search optimization of content.