It is heartening to read about the formation of a working group comprising the major PPC ad companies including Ask.com, Google, LookSmart, Microsoft and Yahoo!. They will initially define Click Measurement Guidelines, thereby defining a click.
Although this is a start, I'd like to see a consortium of such companies team up with other major web sites such as Amazon and eBay to develop what I loosely refer to as an "IP address score". It would be a multidimensional, not flat numeric, score, and be available to consortium members to use as an additional input to their own proprietary click quality algorithms. It could have other uses outside this click fraud space.