What is Superfetch in windows?

Hi,
Can anybody explain me what is Superfetch in windows?
Is this an important feature by windows that i should use?
Thank you.

This is a new memory management tool designed to allow your frequently used programs additional memory by making better use of your systems random access memory (RAM). Superfetch is a technology where the OS optimizes program loading by creating a special cache. SuperFetch understands which applications you use most, and preloads these applications into memory, so your system is more responsive. This is for what superfetch basically works.
Windows Superfetch

This feature in Vista can anticipate your program usage based on past experiences and makes sure that you have enough memory preloaded when needed. By utilizing the RAM more efficiently programs will launch much quicker because the system does not have to load them from the hard drive. Preloaded to main memory. SuperFetch works with another tool called ReadyBoost. ReadyBoost makes SuperFetch's memory management expandable by drawing available memory from a USB 2.0 flash drive.

Superfetch is better than Prefetch, but it's evolutionary. It's not like it's going to double your framerates in games or anything, but it'll just keep things acting snappier. And if you turn off Aero, Vista might even use less power.

ReadyBoost is a technology in Vista where it can instantly use a USB drive as RAM and thus increase the performance in machines where there is a temporary shortage of RAM. Although USB drives are quite slow when compared to RAM, they are lightning fast when compared to HDDs being used for Virtual Memory.

Sometimes Superfetch may cause a bit of a longer startup as it loads everything into memory and your hard drive is running more to preload this data for Superfetch into system memory. This should improve over time as Superfetch learns by building a profile of your usage habbits and applies this information to it's prefetching decisions.