Nope. The latest worms take advantage of 'vulnerabilities' in web browsers and e-mail programs, though these are typically the Microsoft ones.

The worm is often hiding in the body of an HTML email, so the absence of an attachment is no guarantee. Make sure the 'size' field is displayed in your inbox - a text e-mail is usually no bigger than 6k, but wormed mail will be much larger (Klez is often around 130k, for example).

In other words, you don't need to actually open some of them, they activate when they arrive on an unprotected system, resulting in them spreading even further (I received 'Klez' twice today, and one was a 'returned' e-mail).

The people who write them claim they are trying to demonstrate how bad Microsoft software is, but I'm sure you'll agree that's a bit of a lame excuse. Dogs lick their nuts because they can...

The only way to combat them is to use any means available to ensure they cannot proliferate. One way is to use good antivirus software, and another is to make sure you keep up with update 'patches' to your operating system, which are designed to block the holes the worms use to get in. A bit like bolting the horse after the stable has gone... or summat!

A good analogy is fleas... if all animal owners made sure their pets were kept clean of fleas, the fleas would eventually die out...!

All a bit daft, really...