Google Desktop Search, previously known as Puffin, has arrived. It's a program you can download to your Windows computer, if you have such a thing, that uses your computer's idle time to index files on your computer into a database that's stored on your hard drive. You can then go to Google and click on the new Desktop tab that's available when you have Google Desktop Search installed, and start searching your computer. The service is run completely on your own computer, and Google itself never sees your files, search results, or even searches. Results appear similarly to regular Google search results, complete with snippits, caches, and dates. You can also choose to search by date or by relevance. Many preference options are available. Furthermore, Google Desktop Search works in browsers other than Internet Explorer, including Firefox.

Unfortunately, Google Desktop Search is currently only available on Windows. Hopefully they'll extend it to Linux and Macintosh in the future, but currently the main focus of the service is to combat the new file search system that Microsoft was planning for the next version of Windows (although it looks like they won't make their deadline, which I believe is 2006).

This appears to be a major focus for Google, so we'll likely see a lot of great new things from it in the near future. It was just introduced into Google Labs today.