Ok. The summary: they sell email verification at Spam Arrest LLC (senders must first confirm that their email is a real email and not spam before the mail is delivered). And in doing this work they collect sender email addresses. And they've now sent unsolicited advertising emails to these sender addresses, where they offer their service.
Hmm. Fastest way to kick yourself out of the business? Maybe we do need a Business Darwin Award after all.
At Gary Robinson: Gary Robinsons Spam Rants there's the original article.