Spamhaus writes: "The US Department of Justice went public today with the indictment of Alan Ralsky and 10 others who helped him. Alan Ralsky topped our Top 10 Worst Spammers list for quite some time and was involved in almost any sort spam activity that's being done. His gang frequently sent millions of spam messages per day. In recent years his focus has been on stock spam, and that's a key part of what the US DOJ indicted him for."
Others can cover this much more capably than I, so I'll skip the insight and just link to posts on the topic from various smart folks.
(I recall Ralsky being the guy who cried foul when, a few years ago, his home address was made public, and people signed him up for hundreds-to-thousands of junk mail postal lists.)