I stumbled upon Google's wonder wheel, a great feature that lets you find related keywords.








So far so good. Now, this lets you drill down into each of those keywords and check out the keywords related to those.







So, if you're a search advertiser wanting to explore variants of keywords, this would appear to be a great tool. I use the term 'appear to be', because this didnt work too well for some of the industries Greenlemon's clients operate in (most of our clients are SMEs operating in regional/local markets), as you can see in the two examples below:








Next exhibit below:











Some of the elements here are explicable. For instance, three elements in the last pic are regional newspapers, which also happen to be major advertisers. You could, if you're so inclined, take a sympathetic view and say "oh well, cant really expect much more from a machine, can one?" :)

Some perspective also results from the fact that most other keyword tools arent very accurate in the niches relevant to us.

Having said that, I'd guess Wonderwheel is much more useful for high volume search terms. Like most Google products, it is simple, cool, easy-to-use. Plus you dont have to be a search advertiser to play around with it and have a bit of fun! :)

PS - Here's an easy tutorial on how to begin using Wonder Wheel.