Email is one of the most widely used forms of communication today. Estimates from May 2009 suggest that around 250 billion, with a "B", emails are sent every day. That equates to more than 2.8 million email messages per second, and some of them are not even spam.
Email is faster and cheaper than traditional postal mail, but at least when you seal that envelope and stick a stamp on it, you can have some confidence that only the intended recipient will open it. With email, however, your message could be intercepted midstream and you might never realise it.
Copies and remnants of your message stored on your PC could be compromised as well. You have to take steps to secure and protect your email messages.
Your PC provides easy access to your email communications, both for you and for others. Anyone who happens to walk by your system, whether you're in the middle of using it or have stepped away from your desk, could potentially see email messages you are in the process of writing or have already sent, or your incoming email messages.
You need to take steps to minimise the opportunity for passing bystanders to snoop on your email.
For starters, don't leave your email client open, or at least not maximised on screen. Whether you use a client application such as Microsoft Outlook, or a web-based email system like Google Gmail, you should minimise or close the email window when you are not actively using it.
You also need to make sure that snooping eyes can't see what's on your screen when you walk away from your PC for an extended period of time. Many people know to lock or shut down the PC when leaving for the day, and perhaps even when going to lunch, but they might step out to discuss something with a co-worker without thinking about it.
As an automatic security measure to protect your email, as well as the PC in general, you should enable a screensaver (go to Control Panel/Appearance and Personalisation).
Set a delay before the screensaver kicks in, it shouldn't be any less than five minutes because it is not uncommon to go five minutes without touching the mouse or keyboard while reviewing a document or reading a web page, and having the screensaver come on would be an annoyance. Fifteen minutes is a reasonable timeframe. Make sure you check the box to display the logon screen and require credentials when resuming.
This should go without saying, but make sure you have a secure password. Using your dog's name, or that of your favorite baseball team, won't provide much protection. In fact, you should never use any word that can be found in a dictionary, guessing or cracking them is trivial.
Protecting web-based email
Web-based email has the advantage of being available virtually anywhere, any time and from any device that can get on the web. It also comes with some additional security and privacy concerns, though.
On any PC, but particularly on a shared or public PC, such as one in a hotel or library, make sure you log out of the webmail client. Forgetting to actually sign out could allow the next user who comes along to access your email account.
Web browsers maintain a history of visited sites, and a cache of browser data that help them load frequently visited pages more quickly. The history and cache may also inadvertently expose your email messages. When you are done using your webmail, you can go into the settings for the browser and clear out the cache.
Better yet, use private browsing. The most popular web browsers, such as Internet Explorer, Firefox and Chrome, have an option to surf the web using a private or anonymous mode. When you use the private browsing mode, your entire web session is more secure, since no data is retained in the history or cache.
Whether on a shared computer or your own PC, another suggestion is to use an alternate browser. For example, if the default browser for the PC is Internet Explorer, use Firefox, Chrome or some other browser just for your webmail.
That way, if someone else uses the system, they will likely use the default web browser, so using a different browser will reduce the chances of exposing or compromising your email account.