I noticed on one of the forums that Hubbers had questions about what the Google Traffic Estimator tool is and how to use it.

This short video will hopefully answer both those questions.

The Traffic Estimator is a tool contained within Google Adwords. I was not able to find it outside of Adwords so you probably need an Adwords account to use it. There is a one time fee of $5.00 to join Adwords but it's worth it because you get unlimited access to Google's best keyword tools without those aggravating Captchas.

If you have an idea about the topic of a Hub but are not sure what keyword phrases you should use to build your Hub around, the Google Traffic Estimator will at least allow you to narrow your selections to keywords that have proven commercial value.

We know they have commercial value because Adwords advertisers are paying for them and people who search in Google for those keyword phrases are getting sent to pages with Adsense ads and clicking on them.

The keyword phrases that get dozens or hundreds of clicks every day look very attractive, and they are, but consider that the people paying for those clicks are probably spending thousands of dollars a day to get them.

You can also assume that those clicks are being sent to web pages that are highly relevant to those keyword phrases. What that means to you is that those high click keyword phrases will be very competitive. A web user searching for those terms in Google will be shown initially the most relevant pages in the Google listings for that keyword phrase, and the greater probability is that your Hub page will not be on that short list.

It could be but keyword optimization doesn't happen by accident. If you don't know exactly how many backlinks you need to your Hub page to get a position above the fold on the first page of Google, and exactly what you have to do to get them, then the keywords in the middle of the list in Google Traffic Estimator will give you a better shot at getting search engine traffic.