If you are not aware of how the CSE works, read on.

A Google Custom Search Engine is a plain Google search box...on steroids. You can find the sign-up page by going to Google and searching for "Google CSE". It costs nothing to sign up for the custom search engine.

Basically, what it allows you to do is to customize the search results of a Google search on your site. YOU have the power to make the results very relevant for your niche.

Let's say you wish the niche you are targeting to be one of the keywords "eye problem". You'd first create an optimized site just like normal. But then you would also go into your CSE account and create a custom search engine and populate it with the best possible links you could find for "eye problems". Use all the WebMD type sites you could find.

While in your CSE account you also specify your Adsense account number so all the clicks within it will credit your AdSense account. While configuring the account, be sure to specify that you want the AdSense ads to appear above the search results. In my opinion the custom search engine will generate higher click throughs with the ads above the organic results.

The point here is to make the little search engine VERY valuable for people so they may make several searches with it; thus they spend more time there and may click an ad or two.

Next, on the page above the search box, you can have a heading such as this: "Search For an Eye Doctor In Your Area".

Then in small text you could give an example such as: "Austin eye doctors"

Then when a visitor does a search with his or her town for eye doctors, some VERY targeted AdSense ads will appear. These will have a very high CTR; many of the ads will say "Austin Eye Doctor". People will click!

Like I said, I know someone who is doing this with many different areas and is very successful at it.

Think about it! This puts a whole other twist on how to use AdSense. There are thousands of possible ideas which will work very well. Anytime people might search for exact locations, exact model types, exact anything, is a good time to use a Google Custom Search Engine.