The new application can be launched by clicking on the Google logo on the taskbar or by using the keyboard shortcut Ctrl+Space. It combines a program launcher with a search box and it shows suggestions, web addresses and results for simple calculations.
"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," explains Google.
Quick Search Box is similar to the homonymous feature from Google Desktop, which only shows results from your computer. It borrows the mix of search suggestions and navigation predictions from Chrome's Omnibox, while opening web pages in your default browser.
Google should have released Quick Search Box as a separate application or in a future version of Google Desktop. As it looks now, Quick Search Box doesn't offer enough functionality to replace Windows Vista's search box or application launchers like Launchy, the new feature will certainly confuse Google Desktop users and it's not very clear what's the connection with Google Toolbar.