It's an opinion article from Larry Lessig called A Bounty on Spammers. The basic plan is as follows:
Imagine a law that had two parts—a labeling part and a bounty part. Part A says that any unsolicited commercial e-mail must include in its subject line the tag [ADV:]. Part B says that the first person to track down a spammer violating the labeling requirement will, upon providing proof to the Federal Trade Commission, be entitled to $10,000 to be paid by the spammer.The first part would make it easy to filter unwanted emails.
The second part would allow people who are good at identifying the source of spam to make a profit at it. A lot of these people are working on setting up blocklists and filtering systems that every once in a while cause more harm than good. It may just also make the first part actually work.
Good idea? Bad idea?
If you said good, then what about vigilantes acting in other places on the net? Like the recording industry? Lessig addresses their use of self-help also.