Patent 8108388 was granted and assigned to Microsoft on January, 2012 by the United States Patent and Trademark Office.
An alert search mechanism is used with search engines such as a crawler to search for desired documents and/or resources. Particular documents are found by using search queries. The search mechanism track values of a set of relevant properties in queries. Whenever a document is searched for by the system, the values of these set of properties are matched with the old value. If there is no match, this is an indication that the document has changed.