Is desktop search secure?

I love Google Desktop Search. I use it every day. I particularly like the fact that it now supports indexing of Thunderbird. I wouldn’t use it if I was in a purely OS X environment, because the search in Mail, iTunes, and Sherlock in general work so much faster and better than anything in Windows, it’s ridiculous. I’m looking forward to the new built-in desktop search, called Spotlight, that will be a major feature of OS X 10.4 (Tiger). But, since I have to live in a Windows environment at work, Google Desktop has become a valuable tool that I use on my WinXP laptop.

Having read this piece, though, I’m wondering more about privacy and security concerns.