Here is my theory about what is happening. I admit that this is just a wild guess. I believe the spammers have found a way to discover the reporting email addresses of all or most SpamCop users. This could have happened through some brute force attack or maybe a server that stores these addresses got hacked. Or maybe they found the algorithm that generates these email addresses. Or maybe the reports that are sent out allow the recipient to find the reporting address. Now the attacker can send millions of random fake spam mails to these addresses through their botnet. The result is that the reporting server is brought to its knees and that user accounts (including mine) get disabled for reporting too much spam. The problem is difficult to fix because even if the reporting addresses are changed the attacker might still use the same method to find them again. If this theory is true the attacker could not only create a DOS condition but he could also falsely report innocent SMTP servers, which would lead to additional damage. Again, this is just a wild guess and I don't have any evidence that my theory is correct. I usually only report through the web interface and not through the reporting email address, so maybe I don't even understand this process completely.