Most of us get spam trying to sell us things, most commonly prescriptions, cheap mortgage rates, online gambling and other, more "adult" topics. Most of us just delete them or hit the "spam" button and move on. There are some other types of spam that are a little more serious, however.

Spammers are increasingly using PDF files to bear their spam messages. This practice begun in mid-2007, primarily as a scam to fool recipients into investing their money in the stock of a particular company of their choice.

In response to the growing threat from spam, new legislation was enacted in 2003. it was called: Controlling the Assault of Non Solicited Pornography and Marketing Act (CAN-SPAM act). This act created some requirements for all companies who are sending bulk commercial email, as well as those companies whose products are offered for sale in the spam emails. It also instituted penalties for violators, as well as giving the client or consumer the right and the means to request that the mailers cease the spam efforts.

Much like human viruses, computer viruses run the gamut from the benign to the fatally destructive to the computers they infect. And just as with human viruses, prevention is better than cure. Prevention begins by stopping them in their tracks at the portals of contact. This is where a firewall can come in handy.

With spam protection you have to stay ahead to the trends. Because when spam started a crossposting tool was invented to block spam but spammers were quick to adopt crossposting as a tool of their trade. Now, they could send the same electronic message to thousands of newsgroup members at the one time. Not only could they target a larger audience with one posting, but they also did not have to differentiate between the interests and focus of the individual forums that they targeted. What's more it cost them next to nothing to spam these newsgroups.