Google’s old keyword tool is pretty useful.
But they’ve just released a beta version of a new search-based keyword tool.
Here’s the AdWords blog post on the subject. The main idea is this:
Here’s the scoop: you know that the Google search engine starts with searches conducted by users and helps them find relevant pages. But for keyword targeting, what you want is a tool that goes in the opposite direction by starting with your pages and identifying keywords that potential customers are searching on to find your products or services. The Search-based Keyword Tool does exactly this, leveraging search query data relevant to your website’s content. In other words, this new tool gives you keywords that are highly relevant to your site but are not part of your AdWords campaigns. This helps you take advantage of missed opportunities.
I’m sure just about anyone who is at all interested in SEO will be taking advantage of this new tool.