Click to Listen In Mac OS X Leopard, the Spotlight search has been greatly improved. One thing that it does now is bring up your Safari web surfing history in the search results. For whatever reason, you may want to keep that history private, and not have your web browsing history show up in your spotlight results.
How to do it:
1. Apple Menu -> System Preferences
2. Choose Spotlight 3. Choose the Privacy tab and then Select the '+' sign and then navigate to YOUR HOME FOLDER -> LIBRARY - > CACHES -> METADATA -> SAFARI -> HISTORY and select Choose Now Spotlight will no longer index your Safari History and display it in your Spotlight search results.