Google officially launch its custom search engine to the public bringing in more personalized search based on users site or web pages they specify.

The search can be found here http://www.google.com/coop/docs/cse/ and you can create you own search based on your perspective. You can also choose the functionality and other added things at your own convenience like filtering sites and results.

You can also make money using their very own adsense program that can be integrated in the your personalized search engine. You can also ask you friend to contribute in your search engine as you desired. This is a big implementation in google and this could also help to prevent spam sites to come up during your search.