You might refer to it as The Law of the Few, the 80-20 rule, the Pareto Principle or — if you’re angling for serious math geek cred — the principle of factor sparsity. All these names are used to describe a major factor in epidemics or epidemic-like phenomena: widespread effects are often caused by a few key players. Malcolm Gladwell cited all kinds of examples of this phenomenon in The Tipping Point: the transformation of Hush Puppies into a trendy shoe brought about by a few “influencers”, the success of the book Divine Secrets of the Ya-Ya Sisterhood thanks to devoted fans with personal networks and how an gonorrhea epidemic in Colorado Springs was traced to a small number of people in a half-dozen bars.
It seems that the same principle applies to spam and spammers. According to The Spamhaus Project’s ROKSO (Register Of Known Spam Operations), 80% of all the spam out there is being created by a mere 200 operators. To make it onto the ROKSO, you have to have had your services terminated by at least 3 ISPs for spamming.
A snippet from the sidebar of the ROKSO page:
80% of spam received by Internet users in North America and Europe can be traced via aliases and addresses, redirects, hosting locations of sites and domains, to a hard-core group of around 200 known spam operations (“spam gangs”), almost all of whom are listed in the ROKSO database. These spam operations consist of an estimated 500-600 professional spammers with ever-changing aliases and domains.
For those of you who really want to stay on top of the spam underground (or maybe you’ve got a fascination for things like the FBI’s “Ten Most Wanted” list), Spamhaus also publishes a “10 Worst Spammers” list, updated weekly.