It's a longer read than the average blog post, but Joe Holcomb's assessment of the current state of click fraud is worth more than a glance. It's interesting to hear the observations of someone who sits on both the advertiser and PPC engine side of the fence.

The solution to click fraud according to Joe?

"The solution to the click fraud problem lies solely on the shoulders of the PPC’s to invent the technologies necessary to stop click fraud from taking place. The pay per click industry is looking awfully dirty lately. How do we clean it up? Force the engines to change their ways. Speak with a louder voice and withhold your ad dollars from the engines that don’t comply. Work with SEMPO, the SMA-NA, and other marketing organizations to bring these issues to the forefront of the industry. Nothing speaks louder than money. Choose not to spend a dime until the engines solve this problem."