I was listening to Steve Czaben on Bob and Brian's morning show this morning and he brought up the Sobig virus that is currently running rampant on the Internet. His take on things is that email is dead and this virus has killed the Internet. Steve is funny and makes my morning drive worth it every morning, but thank God he only does sports. The only thing he got right in his entire rant was that it's due to people that just don't THINK when they get email with file attachments.
I've got a ton to say about this, but I'll try to keep it short and to the point. There is NO REASON IN THE WORLD that ANY corporate mail server should allow mail attachments that can be directly executed. This includes .pif, .scr, .exe, .vbs, and the whole remaining list of executable extensions. Period. You have now solved 80% of the problems with a virus. You've reduced the corporate cost of these things while reducing the chances of it infecting large networks. Our mail server doesn't accept these attachments and we're not infected. In fact, I haven't even received a single message infected with this virus because our mail server drops them before delivery. Strangely enough, I've gotten several infected messages to my Yahoo! email account, which is the first time in at least 6 years that I recall getting an infected message through Yahoo's servers.
If someone wants to send you one of these attachments, they can ZIP it. Can a virus ZIP itself as well? Sure. But you're injecting another step in to the infection process and making the virus more complex. Making things longer, more complex, and injecting more steps in to a process is the formula for failure for two reasons. One - it's tougher to code and get it right which should cause most poorly written virii to fizzle and die before they get anywhere. Two - I have no faith in the general public as computer users. Take a sampling of people off the streets and ask them what a ZIP file is. Most won't know what to do with it. Even if they have WinZip or WinRar installed, they still have to extract it, find where they extracted it, and execute it. You get the general picture.
The worst side effect of the virus is, of course, the massive email traffic it generates. But frankly, spam is so rampant these days, I see no reason why a virus should add any more strain to mail servers than the latest Viagra mailing.