We are running url shortening service (similar to bit.ly and others) which is quite popular and used by many people. We are not redirecting immediately, our user has to click a button to go to the link. He can see where it goes before he clicks. But spammers are using our service too. Our ISP is threatening us that our links were found in spam. But for us there is no way to know if link is ok. What can we do? Is there any way to check these urls before they are spamvertised (we use malware check already for all shortened links)? Can we ask spamcop not to send us their warnings?