I think it's to do with your yahoo account. You may have previously clicked on one of these links and because it contains malicious code it gives them access to your contact list => all your contacts get this message without you knowing.
I think the solution is to sign out of yahoo often, and change the password.
--- On Fri, 7/6/13, Tom < wrote:
From: Tom >
Subject: [new_distillers] Re: RE:
Date: Friday, 7, June, 2013, 10:56 PM
I did not send the original message. I don't know how this happened.