Wired ran an interesting article recently about how the U.S. Government is using topic maps to provide context for words that have multiple meanings. This would help infer meaning in examples like: Mustang car or Mustang horse?
This is the challenge for search engines as well. Clustering tools like those offered by Vivisimo’s Clusty search engine appear to be quite effective, but not widely adopted. A search on “Mustang” clusters groups of search results according to topics like “Parts”, “Horse” and a town in Oklahoma. This is a lot more helpful than a similar search on Google which displays mostly car web sites in the first page of results.