There is an ugly new permutation of the Melissa email virus that appears to be auto-responding to messages you sent to other people. Here's what happens: You send an email so someone--anyone, a friend, co-worker, whoever--and then receive an auto-reply that looks like it was sent from that person. The message reads as follows:
I received your email and I shall send you a reply ASAP.
Till then, take a look at the attached zipped docs.
I actually received an auto-reply like this today from someone on the WinInfo mailing list. However, it's pretty clear that this person knew nothing about the virus and that's what really makes it so dangerous. Thanks to an earlier warning from Mike Gates, I knew not to open the attachment (and I probably would have: I was sitting there wondering what kind of person would attach a 250K file to an auto-reply when I remembered the virus warning from Mike).
So what can you do to protect yourself? First of all, be on the lookout for auto-replies with the above quoted message. If you're using an anti-virus program (and you should be; so should I: After this little episode, I updated mine immediately) check their Web site for an update. I know that Symantec's Norton Anti Virus has already been updated, for example. They have a great explanation of this virus on their Web site as well.
In short, be prepared. And be aware of this issue before it surprises you, as it almost did to me.