A hoax. The text of one such email follows:

This computer has just been infected by the Discount Virus.

Due to budgetary constraints we have had to let our programming staff go. We are counting on you to use the honor system.

Please erase all of the files from your hard drive and then send this message to the first 50 people on your mailing list.

Remember, hoaxes cost companies - and people - time and money. Please do not forward them to others.