You can easily set up your Google Analytics account to track the search feature on your DotNetNuke website. It's simple, here's how…
Login to your Google Analytics account and click on the edit link from the initial account overview screen to begin customizing your website search account properties

From the Profile Settings screen, you can set up specific properties just for this website. Click on the Edit link to begin making changes.

Under the Site Search section, make the following changes:
That's it. Within a day you should be seeing your results in your Google Analytics reports. You can find it under the Content Section

And now, you can get all the details from your DNN Search feature laid out in familiar and thorough Google style

And since you're already here…..
Since you're already in the Google Analytics account anyhow, you can also add settings to EXCLUDE from your reports. For example, by using "edit" you can tell Google to NOT TRACK any information where the parameter "edit" is found in the URL. What this means is that when you are logged in and making edits on your website, you will not be counted in your site reports. This can help give you a more clear understanding of your site's usage or at least not give you a more true picture. There may also be other parameters you want to exclude. Just check the QueryString parameters in your URL to see if there are any more you may want to add.

Very Easy!