When Google crawls the Web to collect information about objects or entities, it also collects facts about those entities. These facts are separated into different categories or attributes associated with those entities. For example, a book may have attributes such as an author, a publisher, a year published, a website it can call home, a genre, and more.
Identifying Entities by their Attributes
A search that includes those attributes can be used to identify the entity the attributes might be associated with.
Google was granted a patent recently that describes how those attributes could be searched within an attribute data store to find the entity. The patent shows how the process described within it might be used to answer some complex queries, and some interactive Answerbox type queries. The issue that this patent addresses can be summed up in a single question: