...through a classifier of some kind and then use different ranking algorithms for different queries. Note that classificationcan work like Borges' Chinese Encyclopedia: http://www.multicians.org/thvv/borges-animals.html...
http://www.seobook.com/googles-relevancy-algorithms-change-keyword
...recipient, or metadata – such as a word or phrase within the message, or the message classification. Message classificationcan be applied by a user or rule, such as confidential or personal. Among the common uses An Overview of Exchange...
http://www.vancouver-network-support.com/support-files/exchange2007.pdf