If you don't hit the delete button too fast, you may have noticed that your spam messages are changing. Big time.

What was once ludicrous come-ons for penis enlargements or lascivious offers for a peek at pornography is now a hotbed for financial scams and a black market for fake pharmaceuticals and software. The BBC News Online reports that spam is subtly shifting from nuisance to illegality, according to the British security firm Clearswift that has measured spam message topics for the past year. "Spam is now being used as a channel for a plethora of malicious and illegal activity," technical director Alyn Hockey told the BBC.

This is what makes up the spam pie:
Finance: 39 percent
Healthcare: 30.6 percent
Other: 15 percent
Direct Products: 9.6 percent
Porn/Profanity: 4.8 percent
Scams: 1 percent

Why are you now seeing more spam e-mail hawking a miracle diet rather than porn? Hockey says porn has been drastically reduced thanks to improved filtering technology. While porn has dropped to 4.8 percent of spam, compared with 21.8 percent a year ago, financial and pharmaceutical spam messages (read: Viagra) now make up nearly 70 percent of these annoying e-mails.

The dirty little secret of spam is that it works. Enough people respond to it to make it a viable business model. Hockey estimates that spammers have a one in 40,000 hit rate for the products they sell online. One reason for their success is that spammers pay attention to what's going on in the real world. "When Arnold Schwarzenegger was campaigning to be governor of California, there was lots of spam about offering Schwarzenegger memorabilia," Hockey told the BBC. Just watch. Toys and games will dominate before Christmas, and miracle diets will land in your e-mail box after the new year.

The scariest spam messages of all are those that try to steal information from you, including your Social Security number and credit card numbers. Click on these messages, and you'll go to what looks like a legitimate site, but the personal data you enter is stolen from you--something called phishing.

Hackers and spammers are joining forces, trying to infect home PCs with Trojan horse viruses that turn them into zombie PCs that can be remotely controlled without the owner's knowledge. Hockey predicts all this illegal activity will get worse before it gets better, but like pornography, it will eventually decline. "Pornography was offensive so there was a real push to try and stop it, and the same will become true of phishing once people become aware of it," Hockey told the BBC News.