Apple released an update to Safari, plugging some security holes and bringing some performance upgrades as well.  Security patches should generally be applied quickly to keep your system free from hackers.  Webkit is the component of safari getting the overhaul, so Apple’s Mail program is being made safer with this update as well.

The update claims to have “Improved Javascript performance”.  There is no direct documentation of how much performance we will see, but more speed is always a good thing.  The final item listed is “Improved Full History Search performance”.  Spotlight in Mac OS 10.5 and 10.6 has been very fast everywhere else in the system, but many users (myself included) have found that searching Safari’s extensive history is painfully slow.  Hopefully this update addresses this problem.

The Safari 4.0.4 update is available via the Software Update program, or at http://support.apple.com/kb/DL877.