BusinessWeek has an interesting discussion of click fraud:

The spreading scourge known as click fraud poses the single biggest threat to the Internet’s advertising gold mine. A raft of scams and deceptions inflate advertising bills for thousands of companies of all sizes, and is the most nettlesome question facing Google and Yahoo, whose digital empires depend on all that gold. Executive Editor John Byrne in a conversation with Business Week columnists Ben Elgin and Brian Grow.

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