I used to get asked occasionally (when i still worked tech support on the phones) - Why do people write viruses / hoax letters / etc. and I could never come up with a good answer - i always believed its mostly a 'Because They Can' issue.

But with something like this, what better way to get back at someone you dont particularly like, than to write an official sounding email, mass mail it out to a ton of people (while requesting they pass it on to a hundered of their friends) with the real name, company and phone number of that person? Also, using real companies and such lends credibility to the hoax (like a little truth always lends believability to a lie).