I recently deployed Joost de Valk‘s awesome Google Analytics for WordPress plugin on a few sites. (I mean, he even SEO’d the plugin name, how brilliant is that?) One of the features of this plugin will add custom parameters to the URL in your _trackPageviews call so that you can gain insight into what kind of results you return.
For example, if you search for “K-Stew” and get no results, that will get tracked in GA as [“_trackPageview”,”http://www.example.com/?s=no-results:k-stew&cat=no-results”%5D. Great for being able to view GA reports and realize, hey, people want to see K-Stew and I’m not giving them any!