Spam Breakdown

Spam hardly needs an introduction or a definition. Even the most nontechnical person on the street will know exactly what you're referring to when you mention spam. If you have an e-mail address, the odds are massively in the spammers' favor that they've found you and unpleasantly surprised you with offers of drugs, women, and buried fortunes. The most basic definition of spam is unsolicited e-mail -- any e-mail sent to you that you did not request. This is deliberately a very broad definition, especially because spam is now a legal term!

As you've probably experienced, spammers send huge amounts of identical e-mails to as many e-mail addresses as they can. The reason for this is economies of scale. A spammer can usually expect less than 0.5 percent of the e-mails they send to be opened, regardless of whether they're read or acted on. For reasons covered later in this lesson, if an e-mail is simply opened, it's considered a positive response. Therefore, the more they send, the higher the amount of positive responses the spammers can generate.

Basic spam -- the type that simply offers you products and services from a usually reputable retailer -- is little more than annoying. Although larger companies (and those with common sense) have realized that sending spam can quickly alienate potential customers, a significant proportion of companies continue to do so. A fair number of the culprits are those advertising free services, such as free online dating, free classified advertisement listings, and free small business directory entries. Because these companies are little more than legal shells, they have little to lose and lots to gain by spamming their wares.

Spam has implications far beyond being annoying. Studies show that  spam makes up 60 percent of all email traffic. That's an astonishing volume; spam on its own accounts for more data than all of the Web browsing, FTP file downloading, P2P file sharing, and all other Internet services combined. This huge volume of data clogs the available bandwidth on which the Internet runs, making everything else run much slower. The Internet as a whole would be noticeably faster if spam was eradicated right now.

Most concerning is the increasing trend of malicious spam. Customers of almost every major international bank have been targeted by phishing scams of varying sophistication. Phishing is the term given to a specific type of spam that attempts to fool people into supplying confidential information -- the spammers are effectively "fishing" for whatever information they can find.

If you've had an e-mail address for any length of time, you no doubt noticed a gradual increase in the amount of spam you receive (if not, you're one of the lucky ones!). And if you were unlucky enough to accidentally open spam e-mail, you may have noticed it was quickly followed by more spam. It's no coincidence -- spammers use clever tracking mechanisms to monitor whether their e-mail is deleted, opened, or even forwarded to another person.

The most obvious and basic tracking mechanism is a read receipt. A read receipt is a flag in the e-mail header that tells your e-mail client to return the status of the e-mail to its sender. Through this system, the spammer can obtain basic information about whether you read or deleted the e-mail. Every popular e-mail client (such as Outlook or The Bat) has an option to deny read receipts for public e-mail received from the Internet. If you use a corporate e-mail system, such as Microsoft Exchange, the system administrator usually has the ability to force your e-mail client to return read receipts -- so beware!

A more sophisticated tracking system is achieved through Web bugs. As you may know, adware systems can be used to track your Web browsing and application usage habits. The same principle applies to e-mail. Using HTML e-mail, a spammer can include a reference to a script on its server that's executed every time the e-mail is opened and the content is loaded. To achieve this, a single pixel, transparent GIF image is included in the e-mail. This GIF is invisible to the reader, but essential to the tracking system. When your e-mail client loads the image, the tracking script on the spammer's server is executed, completing the vicious cycle. This is the reason you should never open an e-mail you have good reason to believe is spam.

Unfortunately, spam is something that will never stop. Companies and individual spammers make huge amounts of money by selling valid e-mail addresses to one another. Once a spammer gets a positive response, they can sell that e-mail address to other spammers as part of a validated e-mail list. Once your address is on one of these lists, it's impossible to remove it. As you may already know, clicking a link in the e-mail that purports to remove you from the spammer's list is a surefire way to receive even more spam.