Email has become an important part of modern-day life, whether personal or professional. When the email growth explosion began eight years ago, the challenges posed by the modern threats we face today were not even imagined. The threats are, of course, unsolicited bulk email (also known as UBE, spam, or UCE for 'unsolicited commercial email') and virii/worms (also known, collectively as malware, short for 'malicious software').
Spam may seem little more than a nuisance, not causing real harm to any individual user. However, it's estimated that over 20% of all email traffic on the Internet is spam. All of that traffic consumes resources in the form of bandwidth, processor time, and disk space; for larger companies it can even visibly impact the bottom line by requiring more or more expensive email servers and higher than necessary bandwidth bills.
For the end-user, the impact is somewhat different: legitimate emails can be mistakenly deleted while wading through the hundreds of spam messages that can be received in a single day. In this context, spam steals a resource much more precious that computing time: human time.
So what can be done about spam? The answer: software. Anti-spam software is proliferating in response to the spam menace. The software takes four basic approaches: