Originally by Kevin Hughes, EIT, now enhanced by a team at the Berkeley Digital Library SunSITE, University of California. Of the search engines in this section, this is the easiest to install if you want to index only your own files rather than an entire server. Well documented, even with it's own mailing list. Can limit searches to specified html tags, such as meta tags, titles or headings. Testing by the author suggests that it is substantially faster than any of the other search engines listed here.
Documentation is terse but adequate.
Rod Clark, Small Hours. A new indexing search engine, free for the first 10,000 documents. Already has a good number of high profile users. You need root privileges to install it. For high end commercial search engines capable of handling very large sites, see the reviews by the US Department of Education and Network Computing Magazine .