Unfortunately, I have friends who mail me all this stuff, and they constantly ask me, "Did you get the forward? You know I forwarded something to you right? Did you like it?" etc. So I have to read them.
I'd tell them off but I kinda want to stay friends with my friends. (^^)'
I have had talks with my friends who do this kind of thing, but they always seem to be deeply and personally wounded if you ask them not to send you every little joke or picture that they get.