Dearest Laocoon :
I hate to break to you, but this is one of the oldest hoaxes there is. I’ve seen variants on this warning come through on other listservs, one involving some kind of fruit that was supposed to kill the people who ate it and one having to do with something called the “Midas Touch.” Here are a few tipoffs that this is a hoax:
1) This “Forward this message to everyone you know” stuff. If it were really meant as a warning about the Greek army, why tell anyone to post it to the Phoenicians, Sumerians, and Cretans?
2) Use of exclamation points. Always a giveaway.
3) It’s signed “from Poseidon.” Granted he’s had his problems with Odysseus but he’s one of their guys, isn’t he? Besides, the lack of a real header with a detailed address makes me suspicious.
4) Technically speaking, there is no way for a horse to overwrite your entire city. A horse is just an animal, after all.
Next time you get a message like this, just delete it. I appreciate your concern, but once you’ve been around the block a couple times you’ll realize how annoying this kind of stuff is.