The Search Service supports the creation of specially purposes indexes for Full Text Search.
Search represents Full Text search. The indexes that it creates and uses are entirely separate from and different to those of the Index Service. Full Text Search provides extensive capabilities for natural-language querying. These include:
Language-aware searching; allowing users to search for, say, the word
beauties, and additionally obtain results for
Scoring of results, according to relevancy; allowing users to obtain result-sets that only contain documents awarded the highest scores. This keeps result-sets manageably small, even when the total number of documents returned is extremely large.
Fast indexes, which support a wide range of possible text-searches.
The Search Service requires the Data Service, but does not require, and has no relation to the Index Service or Query Service.
For extensive details on how to use the service, see Full Text Search: Fundamentals.