Desktop searching is the latest thing. As hard drives expand and the amount of data we store and use balloons, we need something to help effectively access the information stored in emails, documents, web pages, contact lists, entertainment and all the other files stored on a PC.

The aim is to do this as smoothly and quickly as you can access information on the internet, so who better to help you with this task than the most popular search engine on the internet with its new, free Google Desktop Search (GDS) tool?

However, although Google's GDS tool has useful features, in a test of the beta software, it also appears to be a potential security nightmare. Unfortunately, Google did not respond to requests for comment on these issues.

Google is not the only major name on the web taking action in this area. Microsoft, which also declined to be interviewed for this story, recently announced plans to release new desktop search technology by the end of the year. AOL, which already offers local search, multimedia search, image search, news search and product search, has acknowledged that it, too, has developed a beta desktop search product. And Yahoo also has a desktop search tool in beta, but it wasn't willing to let us look at it just yet.

Software makers Blinkx , Copernic Technologies , and X1 Technologies already offer desktop search tools as well. The Blinkx and Copernic tools are free; X1's tool is $74.95 (£40), though there is a free trial version).

So how good is Google on the desktop? To find out, I took both GDS and Copernic's well-regarded Desktop Search (CDS) tools out for a spin.

GDS downloads and installs in no time. Although I had to free up some space to finish the install (GDS forces you to have 1GB of free space on your C: drive, even if you have another drive installed with ample room, as I did), the application immediately sets out building a central index of your entire electronic existence – but only on the C: drive.

It took a little more than an hour to index about 20G of data – not including Adobe PDF files, which the beta version does not index. The indexing takes place in the background, however, so you can continue to work while it does.

When finished, GDS adds a small, colourful icon to your computer's start menu, which launches the software with a double-click. GDS has the look and feel of Google's familiar internet search engine.

Users will discover that they can go to on the internet and find a "desktop" tab waiting for them there as well. This allows users to easily switch between searching the internet and searching their desktop, or even to integrate the two into a single search of both their PC and the web.

However, a search produces an uncategorised list of hits ranked by either relevance or date, just as a Google-only search does. As with search engines in general, a highly specific search with GDS will yield on-target results. But if your request is more general, you might have to wade through long lists of web pages, Word documents, Excel spreadsheets and instant messaging texts when all you're searching for is an email message.

In contrast, CDS offers a user interface that assists you in sorting and finding data. CDS works as fast as you can type, and your results are sorted according to file type and date. Unlike GDS, Copernic's tool can find PDF files and will automatically detect external hard drives connected to your PC and index them as well.

But one thing that Copernic's free desktop search engine doesn't do is include secure web pages in its index. And that's a good thing, since secure web pages (those whose URL starts with "https") include things like online banking statements and ecommerce sites where your credit card information resides.

With Google's tool, unless you indicate otherwise either at installation or later, all such information is included, even though such pages are supposed to be secure and accessible only if you have entered the correct user names and passwords for your protection. GDS does, however, let you easily select the types of files you want indexed via its Preferences page.

GDS doesn't offer much else in the way of features or customisation. Users can restrict the program from indexing portions of their hard drive or other sensitive information. For example, the GDS Preferences page allows the user to enter files into a "Don't Search These Items" box. However, the user must understand exactly where that data is stored and how the Windows file structure works.

GDS even indexes and caches hard drive data protected with an encryption program like Pretty Good Privacy. How? It's simple: GDS adds all viewed documents and pages to its cache – after you've gone through the security handshakes. (Go to Preference to turn off this capability if you miss it during installation. Note that any secure pages GDS already has in its index remain there, but they are hidden from search results unless you choose to include them once again.) I couldn't find any way to stop GDS from caching PGP files or drives--it's similar to the problem this tool poses with the secure Web pages.

And GDS stores its painfully complete index in one "convenient" location on your hard drive, with no encryption or password protection – a hacker's and worm writer's dream come true.

Copernic, in contrast, enables users to select exactly what they want to index using a simple and familiar graphical dialog box that shows the file-tree structure. And they can restrict indexing to a particular hard drive partition or to specific mail folders within Outlook. Users can also decide to index all contacts in their global Exchange address book, or only personal contacts in Outlook.

Copernic users also enjoy greater control over their searches. For example, they can set the application's advanced Preferences so that it skips photo files that are smaller than 16x16 pixels, or music files that are less than 10 seconds long. And if extremely large files are a concern, users can manually set (in General Preferences) a size limit for files to be indexed. Those files will always be excluded from searches.

Desktop search is a wonderful concept. Using either of these products can save you time. However, Copernic's tool offers certain protections, thanks to the way its software is structured. With Google's tool, you might do better to wait until its security flaws are addressed.