What does it do? In short it is a quick way to get a pop up box and search Google without searching for your browser. It is similar to the gadget in Google desktop, but much simpler to manage.
UPDATE Just to clarify this does not constantly scan your disk like Google Desktop Search and eat up resources.
The neat thing is, aside from simple Web searched, it also finds basic things on your disk like programs (e.g. Notepad) or files in My Documents. It looks to me to be similar to Spotlight on the Mac. Actually on apple it has many more features. The basic features are described here.
On Windows it is only available with the Google IE toolbar. But it works fine even if your default browser is something else (like Firefox). You don't even need IE to be open, just installed. But, there are 2 glitches.
- If you already have an old version of the toobar for IE installed, you need to uninstall it.
- On some systems simply installing the toolbar by itself won't work. For me I had to install it via Google Pack. Just be sure to select IE toolbar in the pack.
Try it and let me know!