This column appears in the February 06 issue of PC Advisor, onsale now at all good newsagents.

Many years ago, in the heyday of DOS, Lotus brought out a desktop search program called Magellan that did several amazing things. It indexed your entire hard drive and kept that index up to date. It let you search for anything in any file on the drive, no matter what the format. And it displayed the contents of what it found in a handy preview pane located right next to the list of relevant files.

Magellan’s followers became fanatical about the program, which suddenly made the content on the drive more important than the filenames. But then, amid loud gnashing of teeth throughout the land of DOS, Lotus killed it off.

Today, desktop search is everywhere – and usually free, as it is in downloadable apps from Copernic, Google, MSN and Yahoo. It’s also integrated into Mac OS X Tiger and the forthcoming Windows Vista.

So what’s the big deal? Well, it’s the same as on the web: desktop search unlocks highly useful information that was previously hidden inside otherwise impenetrable files. But the key to its usefulness is the way that information is presented – and how you can filter that presentation. That’s why I currently use – sorry, make that practically live in – Yahoo Desktop Search.

When I want to find information that somebody sent me about podcasting, I just type the word into Yahoo Desktop Search’s window and instantly see a display of every file on my drive that contains ‘podcasting’. YDS presents those results as a file list with a preview pane.

I can further restrict the search with Boolean operators (AND, NOT and OR), limit the search by type of data – email, attachment, document, picture or instant message – narrow results by filename or mail sender and sort by date or other criteria. When I find the nugget I want, I can open it with a single click. All of a sudden, desktop search becomes the place where I go to start looking for anything.

Search proponents have been known to take this power a bit too far: why bother keeping an address book of your correspondents? A couple of keystrokes and you can extract their phone numbers from emails. Why categorise mail when you can search your inbox in seconds?

Not so fast. One reason to keep an address book is so that you can transfer it to and from a phone. And one reason to categorise mail into folders is so you will have everything related to, say, a particular upcoming conference together in a single place. Not all your mail about the conference will explicitly mention it by name; as a result, even a perfect search might miss relevant items.

But it’s easy to become fanatical about this stuff. Having saved all my email – well, not the spam – I have an amazing database that lets me see what I was doing as far back as the early 1980s. Now it’s accessible, thanks to a search engine that can look into, index and display files
in formats I can barely remember.

I can’t stress enough how useful a desktop search program is. Don’t wait for Windows Vista. Start with Yahoo’s program, and if you’re unhappy with it, move along to one of the others. Search is the most valuable software category since the long-gone Age of Magellan.