Semantic search will be important as it emerges on the web, as well as in other areas like Microsoft's SQL Server database. There's currently some documentation on MSDN for the new semantic search capabilities coming to the next version of SQL Server aka. "Denali". Here are some of the things the how-to covers so far:
- Key phrases in a document
- Similar or related documents
- Key phrases that make documents similar or related
Semantic search builds upon the existing full-text search feature in SQL Server, but enables new scenarios that extend beyond keyword searches. While full-text search lets you query the words in a document, semantic search lets you query the meaning of the document. Solutions that are now possible include automatic tag extraction, related content discovery, and hierarchical navigation across similar content. For example, you can query the index of key phrases to build the taxonomy for an organization, or for a corpus of documents. Or, you can query the document similarity index to identify resumes that match a job description. -- MSDN
The semantic indexes are queried by using three Transact-SQL rowset functions to retrieve the results as structured data.