Note the bibliography of 131 references. This paper describes the technique of Latent Semantic Indexing, and the use of it in experiments with the TREC test collection. It describes the interface, the type of tasks it can handle, and its use of AI planning and search techniques. Here's a local link to the same paper. Given a natural language question, it will examine FAQ files to provide an answer.
Wordnet gives synonyms for words in the query.
The authors discuss work in creating applications that allow users easy access to information. They briefly describe the FAQ Finder . They also discuss the Car Navigator, a system that allows someone to enter requirements for a new car purchase, and see possible matches. This describes some work in creating a personal assistant that makes suggestions to a user examining files in a digital library. It attempts to infer the user's relevancy measure.