Interesting point. I thought Drupal is popular for small websites and spent some time to create a flash demo on how to do scalable full-text search on databases, taking Drupal as an example.
You can create a full-text database search service, return results as HTML/XML/JSON. It uses the Lucene directly in java, but can be easily used with Ruby, PHP, or any existing database web applicatoins.
You can easily index, re-index, incremental-index. It's also highly scalable and easily customizable.
The best thing is, it's super easy. You can create a production-level search in 3 minutes, and you don't need to know Java.