What would I use Custom Google Searches for?

I have seen on other websites a search feature that is powered by Google in order to search topics on a website. Seeing that I am using WordPress, the search feature provided seems well enough on its own. But yet, I may wish in the future to provide a more advanced searching capability.

I found a Google tutorial on creating my own Custom Google Search and the implementation looks to be fairly simple. The original reason I was looking into this is to see if I could provide a search feature with some predefined terms that are relative to my website visitors that would utilize Googles database of sites to retrieve some useful pages. What I was hoping is that i can take that incoming result and do some unique formatting to the result set that is more visually appealing by having my server do some preprocessing of the result set, grab an image from each result page, provide a count of the most often used words (except certain stop words) and maybe a short blurb from that result.

In reviewing the details from the tutorial, I could indeed provide a simple search feature. However, as per the agreement of the service I could not process the result set in my own way. In order to use the service you need to agree to the terms of service and in section 1.3 my obligation would not allow me to modify the results. There is some minor adjustments to the look that can be made, but not to the extent I wanted to use it for. I may have to look to see if there is any other api available out there to do web searches and bring back results. May be easier for me to setup a chron job on the server to run a processing script to look for relevant information to be cached and used within my site. I did this before with a blockwatch website that pulled police reports at 8am each morning from the last three days worth of reports.

I will let you know if I come up with an alternative solution!