I can only imagine what it looks like having our email sending people ads for cheap viagra.

Come on guyyssss, I'd google it, but I don't have time to go on a google tangent and you know that's what happens.

isnt it called email spoofing?

Yeah, it's usually called email header spoofing, or email header forgery. As to how it happens, that's beyond my meagre ken.

http://en.wikipedia.org/wiki/E-mail_spoofing

Is -j. a ken doll?