I remember the fist time I received one, telling me that Mr. no-sé-quién from the goverment of an African Country was hidding and coming to my city, they asked me to contact them... The strange is that he was trying to hide in Buenos Aires?????
It was destined to US candid people
OK, anyway, when you reply a chain you help to spread spam adresses around.
See my example:
I want to collect adresses to spam everybody, so I invent something so stupid like this:
"Bill Gates will donate 3 cents to... African Ape Rescue Society... each time anybody replies this email. So forward it to all your friends!"
"Don´t eat chicken at McChicken´s, they come from a Farm infected with Radiactive tests!!! My cousin has eaten chicken and he has four eyes and his hair is green!! Send this warning to all your friends!!!!"
I send it to 3 people, you included. You send it to 10 friends, 5 of them send it to 10 friends, and so.
After a month, I got my email back, and the multiple replies give me a lot of REAL
email adresses, because I can see who has received it.
I say REAL because people forward the email to people in their contact list.
Now I can make a CD with Real email adresses and sell it to companies that want to spam publicity.