As an alternative for both our very own OK-but-slow search and the
fast-but-never-up-to-date google search, how about
http://www.mnogosearch.org/
Its UNIX version is GPL. It consists of two parts, indexer (crawler) and
search module. The latter can be called from PHP, so we could even keep
out interface. Question is, can we tune it so it updates every edit fast
enough?