Finally, a bit of fun and a criticism. Using all these tools, I indexed about five years of ephemera held in about 3GB of data. Then I used each tool to search for references to an old friend, someone with whom I've shared a few documents and email messages. The following table shows how many separate files each product found. Note that this article was first written just after Google Desktop Search 1.0 was released—that tool therefore looks much better than it did a week earlier, when it was struggling to compete.
Clearly, Google is now working hard to pull out every result, but the Copernic engine performs nearly as well (20 word "stems"), and AutoFocus, which is pretty different to use, is not far behind. It seems as if these three vendors have employed all the best brains.
Finally, in all this testing, there's a clear shortcoming to these search tools. Much effort is spent indexing the disk, but if truth be known, I probably search for a handful of things, and I search for them over and over. I don't look for my shoes just once; I'm always looking for my shoes. Having played with these tools a bit, I don't buy the argument that rescuing me that rare 1% of the time compensates for all the mundane recollection I do the rest of the time. Rather than analyzing what's on my disk, I wish these tools would do a better job of remembering what I've searched for before and what I thought was a good consequential find. If AutoFocus could do that, I'd use it in a minute. It's already able to suggest keywords similar to the keyword I'm currently examining, but it's not yet able to suggest searches I've done before.
In summary, if you have only a few files, a desktop search tool might be overkill for you. More files than that, and desktop search could be a blessing, especially if you're still on dial-up. Install just one or two of these engines, though. Ultimately, they say, we're all searching for something; at least that's a comfort we can turn to when we're jaded with the things that we've already got.
Nigel McFarlane is a freelance science and technology writer, analyst, and programmer. He writes books and articles on open source, web, and Mozilla/Firefox matters, including Rapid Application Development with Mozilla (Prentice Hall PTR, 2003, ISBN 0131423436). See his web site at http://www.nigelmcfarlane.com or reach him by email at email@example.com.