Google explains this way,"Sometimes, multi-tasking on the computer can be a maddening process if you have to constantly switch between different programs and files. Try using the Quick Search Box: it lets you easily search both your computer and the Web from a slick-looking search box that comes up only when you need it,"

The new application can be launched by clicking on the Google logo on the taskbar. If you love keyboard shortcuts, you can also do it by using the keyboard shortcut Ctrl+Space. the program launcher is actually a very good and useful feature.

Quick Search Box is similar to the homonymous feature from Google Desktop, which only shows results from your computer. The Quick Search Box should have been better if bundled with Google Desktop and it is likely to confuse Google Desktop users. This Quick Search Box doesn't offer enough functionality and is unmatched with Windows Vista's search box.