Well, if you haven't realized this yet, Google Desktop is the prototype of Google Operating System. Google Desktop is a complex application that combines a somehow weak search engine with personalized information: news, weather, mails, feeds, system information - displayed in simple containers called panels (or widgets). The idea is to have every single useful information at your finger tip.
Google Desktop aims to replace Windows Search feature (press Windows+F3), rss viewers, mail applications and even Outlook for its basic features. Google Desktop is always on top and may be your information control panel. Most of its functions need an internet connection, but it can be used offline as well.
Google Desktop wants to create a bridge between your PC and the internet: you get what information you want in the same interface, even if it resides on your computer, on Google servers or elsewhere.
So you see Google Desktop is a great concept, but unfortunately it's also a memory hog and it also doesn't remove deleted files. Google couldn't find a way to build a good algorithm for relevancy, so the results are displayed by date. Google wanted to use the browser as a shell for their engine, but couldn't find a way to display the results in a natural way, like in Windows Explorer or Total Commander or other file manager. Maybe you want to delete some files, or just to copy them to a folder, or concatenate them. You can't do that in Google Desktop (maybe you could develop a plugin for that).
In the next post you will see how Google updated Google Desktop and how can you search your desktop PC from your laptop.