New to me: http://www.zilverline.org/zilverlineweb/space/home
This is not a new concept or product space of course. Most recently Google has entered this with its "Google Desktop", and in future Microsoft will embed this type of functionality into its os.
Zilverline is what you could call a 'Reverse Search Engine': Zilverline is a search engine that offers web access to your personal or intranet content. Zilverline supports collections: a set of files and directories in a directory. Zilverline extracts content from PDF, Word, RTF, txt, java, CHM as well as zip, rar, and many other archives. A collection can be indexed, and searched. The results of the search can be retrieved from local disk or Intranet. Files inside zip, rar, chm and other archives are extracted during indexing, and can be preserved for searches. Otherwise they are extracted 'on-the-fly'. You can store indexes and caches wherever you like, you could for instance store them on a DVD, as long as Zilverline (and your webserver) can access them. If you supply a url with your collection, the search results will map to the url instead of the source. This allows you to retrieve your result hits from your webserver, instead of disk. Zilverline is internationalized (English, French, German, Spanish and Dutch), and has support for skins (now three). The French translation was provided by Gilles Azria. Merci! Zilverline is built in Java on top of Lucene and Spring. You need a Servlet Engine, such as Tomcat to run it. I'm using version 5.0.28.