First, click on Hunt Keywords in the main menu, then Brainstorm and then Show. The box shown in the image, left, should appear.

Now check a few web sites until you find one that goes into some depth on the subject you're interested in.

Highlight a large block of text with your mouse (don't be choosy), right-click and select Copy to copy to the clipboard.

Go back to Ad Hunter and click anywhere within the Brainstorm area to add to the list (as shown in the image).

Before doing so, however, set the Word length greater than dropdown box to exclude words of two, three or more letters in length. Only words greater than the dropdown setting will be added to the list (which is a great way to get rid of common words like 'the', 'this', 'that', 'your', 'why', 'where' etc.).

Now, highlight a word in the list and click the Check result button. Your default browser will automatically load up and take you to a Google search page of results relating to the keyword. Are there any AdWords?

But it can get even better! With single words, Google sometimes adds at the bottom of the page a list of words related to the keyword. And some of these occasionally have few - if any - AdWords ads listed.