This search feature is powered by GoogleTM using their Free SiteSearch feature. This feature automatically limits the scope of the search results to pages served from this web site.
Because Google's search index is updated whenever their web spiders get around to indexing this site, searches occasionally will provide bad results if I've moved pages around. However, so far I've only moved pages around once in the lifetime of this server. More commonly, Google will simply fail to provide hits for new content because their spiders haven't seen it yet.
Google's Free Search - Information Services Agreement document requires that the Google logo be displayed beside the search box (section 3.3). I'm willing to suffer this bit of free advertising in exchange for an excellent, zero-maintenance search feature. It also indicates to people what they can expect if they were to do a search.
Observant readers will notice that the Google logo above is a GIF image served from Google's site. As we all should know, GIF is bad. It would be nice if Google would provide PNG format logo images, but it doesn't seem that they do. (I did try to convert the GIF image to PNG format, but the resulting PNG crashed my old Netscape 4.73 browser and I didn't look into it further.)