For a spammer, the use of PDF files is advantageous because PDF files are so commonly used in the business world. In fact, several companies allow or even require their business email systems to deliver these documents to the recipient. This makes it very likely that this PDF spam will reach the user's inbox.

The advent and decline of the different types of spam attest to the cat-and-mouse game that goes on between the spammers and the security experts. As anti-spam technology catches up to their techniques, they continue to innovate and change tactics to deliver their spam messages.

Protecting Your Kids

Like all other Internet users, children are just as susceptible to receiving spam as are adults. And because spam is an equal opportunity menace, kids are just as likely to receive spam that contains adult and pornographic material. While there is really no way to totally eliminate the possibility of your kids receiving spam, there are steps you can take to minimize it.

Whitelists - Set up an email account for your child that "whitelists" only specific email addresses. A whitelist is just a list of trusted and approved email addresses. For example, you can have the addresses of your child's grandparents, aunts and uncles whitelisted. Whenever email is received from any of the whitelisted addresses, it goes directly to your child's inbox. All other email addresses are blocked.

Spammers tend to direct the dictionary attacks at the large email companies, which have a large number of customers, which can be your kid.

Be sure to log into your child's email account on a regular basis to monitor the incoming and outgoing messages, and to ensure that the spam filter and spam block are working appropriately.