We have tried it also and gotten some response out of it but not enough response to pay for the advertisement. My heart belongs to spam because getting the email list is free and emailing is free. But its not so free when your ips get blackholed
If it where legal to do and it didnt cause so much problems and headaches, I'd continue to spam.. There very little overhead and it works. For the cost of a cheap dial up line you can send your message to millions till it gets shut off. Honestly i do beleive that it is truely the best way of getting new customers and the best way to get into alot of trouble. The person responsible needs to consider whether it is going to be worthwhile to deadl with the though of their network being blackholed to the rest of the world.