Spamhaus TOP 10 lists
Spamhaus is a well known organisation tracking spams and spammers. It offers services like the Spamhaus Block List and the Exploits Block List which are both realtime block list to be used with your mail servers. Spamhaus also tracks spammers and publishes data about them:
For example, the worste spammer today is an ukrainian citizen named Alex Polyakov also known as Alex Blood, Alexander Mosh, etc. (Alex Polyakov is the big Soviet spy character in John LeCarre's spy novel "Tinker, Tailor, Soldier, Spy.").
Also interesting: France isn't ranked in the TOP10 list but my french ISP proxad.net is ranked 6th as for today. Proxad's public ISP branch (Free.fr) announced that they will start blocking outgoing SMTP traffic from their clients unless the client manually activate the port on their control panel. I'll sure keep an eye on this list to see how proxad evolves.