You know an application has widespread user support when third-party tools that enhance functionality start appearing.

That's what's happening with Google's Gmail. Some of the tools available for Gmail are so useful that they may very well become indispensable to many.

There are a number of Gmail notification tools on the market, for example, and they all do one very important thing: alert you when you receive a new message in your inbox. The Gmail Notifier (http://toolbar.google.com/gmail-helper/notifier_windows.html) is Google's own notification application.

It sits quietly in the Windows taskbar, making its presence known subtly by sliding a small notification rectangle out from the taskbar when news messages arrive. You can double-click the Notifier taskbar icon to launch Gmail. A Mac version is also available. gTray (http://torrez.us/archives/2004/05/23/272) is a third-party tool that does approximately the same thing as Gmail Notifier.

Many people are reluctant to move to any new e-mail program without first being able to migrate their existing mail to it. That's where the Google Gmail Loader (http://www.marklyon.org/gmail) comes in. This tool works by reading your existing e-mail and forwarding it to your Gmail account. It will not delete mail from your current e- mail program. The solution is less elegant than one that can categorise your mail upon importing, but it does the job, and categorisation can be done in Gmail after importing the mail.

Proving that you can do more with Gmail than send and receive e- mail, Gmail Drive (http://www.viksoe.dk/code/gmail.htm) integrates with Windows to make the space available on your Gmail account look and act just like another hard drive. Given that many Gmail users these days have about 6 gigabytes of storage space available, this utility can really prove useful, since with it, Gmail in effect becomes an online storage repository that you can use to back up, store, or safeguard important files.