"Dear anybody. Your email address has been chosen by our computer. So, for no reason, we'd like to give you a million dollars. All you need to do is give us your bank account numbers. Can we interest you in some diet pills? And, by the way, I want to marry you." I hate to let you down, but there is no "million dollars". The diet pills don't exist - and your future "husband" or "wife" has just proposed to a million others. These and a hundred other stories have been made up to steal your personal information or money or maybe just to infect your computer with a virus. Welcome to the world of junk email. Junk email - or spam - is probably the biggest global business that's ever existed. Billions of spam emails are sent every day, making up around 80% of all email traffic. These incredible volumes of spam slow down the whole internet and cost businesses millions of dollars just trying to keep up with the next trick. Your email programme probably includes a spam filter, which sorts out the mail you do want from the junk. But it's impossible to stop it all and if you put together the seconds it takes to see through the deception   in each one, they add up to a significant amount of lost time dealing with the spam that does get through. But who could fall for such obvious tricks? Probably very few of us - one in a million, perhaps. But when you are sending billions of these every day, for next to no cost, it doesn't take a genius to work out that someone is getting very rich. But who? It's incredibly difficult to find out. Most spam is sent using anonymous networks of infected computers, called "botnets", some of which are made up of tens of millions of computers across dozens of countries. Maybe your own laptop is sending out marriage proposals right now. It's enough to put you off using email again! So what can you do to defend yourself? You could set up a separate email account for online use, or maybe leave out the @ symbol when you write your email address online. An up-to-date web browser and antivirus program will help too. And of course, never open strange email, even from a friend's account. Never click on the links. And never ever reply! The passage is mainly about   _  .
the problem of junk mail the profits of junk mail protection against junk mail the harmful effects of junk mail