Why does your url cause a PORN popup and subseqent PORN eMail traffic?

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As Dennis pointed out, your ad states "Loads of calculators for sale ASAP !" But when we select the url you provided http://www.retro-trader.com/ it not only takes us to a website with only one calculator listed, but does generate a pop-up for a PORN site. Then we start receiving PORN emails that tell us that what they are sending is not SPAM but we have chosen to opt-in to their website through another website selection? REFERENCE: http://alt.com/cgi-bin/public/page.cgi?start=1&pid=p10345c