Nice info there, but when you have their IP address, and what you going to do? send an email to their ISP to complain? In my previous job, my company was sending email to all the ISP about their user spam email, after waiting for almost 1 year, still no reply. I bet until now the ISP still no reply. Imagine any ISP with 50% of their 1M users, they have to warn 500K users about their abuse and with 20% of the users terminate their subcription, will they do it? I bet they wont, but you have provide a good job in the detail.

mayb u r right, from million email I have sent, only few reply to my ex-company. But for me, after leaving my company, I just use filter function to drop all the junk email unless I am paid to report all the spam mail.

Keep up the good work.