It's interesting to watch the WWDC 2004 keynote and note when the audience of Mac developers applaud or gasp or groan.

During Jobs' presentation of the new metadata indexing feature in OS X Tiger, the burst of applause came not for the search itself, but when Jobs showed that searches can be saved as "Smart Folders" in the Finder and "Smart Groups" in Address Book. The technology itself isn't the story -- it's these amazing self-updating tools that use the Spotlight tech. Cool.