This is a custom search page, maintained by a Dhamma Wheel founding member, retrofuturist:
http://www.google.com/coop/cse?cx=005450833152705498271%3Ahcbjbznmwso
As exaplained here: http://dhammawheel.com/viewtopic.php?t=5#p832, it limits the search to sites relevant to Theravada and Early Buddhism. It can be a handy tool, and we have it linked off the index pages at Dhamma Wheel. Perhaps something similar could be integrated here.