The Security Mentor

Spying has become so easy now that it's worthwhile for advertisers to plant spyware on your computer just to get a few cents worth of marketing information.

But wait, there's more. If you're a reporter then someone may be targeting you directly. You don't need medication if you suspect someone's spying on you. The ?HP boardroom spying scandal turns out to include private investigators following a journalist and trying to plant surveillance software on another's computer.

...the detectives e-mailed a document to a CNET reporter, according to those briefed on the review. The e-mail was embedded with software that was supposed to trace who the document was forwarded to

says the article. I know two ways to do that(*). It's good to protect youself against both even if you're never a target, because when you protect against those you protect against many other threats. Check your mail program's documentation for how to disable "HTML email" and "Javascript".

(*) One of which also sends back the text of any comments that people add when the email gets forwarded.