And two weeks ago a leading wireless operator launched a 'Peopling service', which connects a smart-phone contact database to Facebook and Twitter accounts.

For a Web application, the data source is commonly a relational database, which has some forms of search built in. (Equality is a simple search operator, as is the SQL operator LIKE.)

The Dictionary Lookup operator is based on dictionaries that contain lists of words to extract concepts, including names, products, or even skills mentioned from textual database columns.