My email address can be circulated amongst virus laden machines as follows:
On Microsoft systems, a common way to manage viruses is to use an antivirus program. This approach has limited effectiveness as the antivirus program is usually updated after the virus is in the wild. The virus therefore has a good chance of spreading before an antivirus program has been updated to identify a virus.
A good way to avoid spreading your friend's email addresses amongst virus infected computers is to avoid using Microsoft Outlook or Microsoft outlook express. Most email viruses look for address lists and inboxes for those two programs.
There are many great email programs which can be obtained at little or no charge. Some have a system which learns which emails are spam (unsolicited sales etc). Others have great mail sorting and relaying functions.
Mozilla is free, has an excellent web browser, web page creator, email system, anti-spam system, address book, chat client, pop-up blocker, anti- mail bug system and tabbed browsing of the web. Users of Microsoft products will appreciate the extra functionality and ease of use of Mozilla. Best of all, it has been written by a co-operative group of programmers trying to make the web a standards compliant, accessible place. By using Mozilla, you support these aims. Mozilla can migrate your Internet explorer bookmarks and your outlook express mail and address books. Mozilla is compatible with a wider range of computer systems than any other web browser. Download it from http://www.mozilla.org.
How to avoid viruses(2)
If you are using a Microsoft based system, do not open attachments in emails, even if it appears to come from someone you know. Only open an attachment if you were expecting that specific attachment. Microsoft systems handle files differently depending on the last few letters at the end of the file name. This is called the file extension. Unless you understand what a file extension is, and what a dangerous file extension is, don't open attachments.
Dangerous file extensions for microsoft systems include: .scr .exe .com .pif .bat .vbs .doc. Once a user has executed (run, double clicked on) a file with one of these extensions on a microsoft system, the system may have been 'compromised'. Once a microsoft system has been compromised, the person who wrote the virus / trojan / worm can control the system as if they were sitting in front of the screen, holding the mouse and keyboard. Your personal information or anything typed into the keyboard can be relayed to the agency which now controls your system. If you are using an office network and you accidentally open a virus/trojan/worm, your system may be used by the unwelcome code as a staging post to undermine the corporate network. If an administrator logs into your machine at any time after your microsoft system has been compromised, the administrator's credentials can be sent to the virus writer's system to later gain unauthorised entry into the network.
If you are using a unix-like system such as GNU/Linux, BSD, Solaris, AIX etc. There is less risk from users infecting a system, whether intentionally or unintentionally. Worms/viruses and trojans are rare in the wild for unix like systems. An infection with such a worm/virus/trojan would most likely be as a result of a focussed effort rather than a random infection. The effects of such an infection would likely be benign as, unless an exploit exists which the worm was specially crafted to use, the worm will not be able to cause a compromise outside the user's own account and home directory.