As pay per click gets more and more integrated into the search field, more and more people will be trying to fraud competitors to get ahead. Some terms such as "mesothelioma" (asbestos cancer) cost over $60 per click on top search engines. My recent check of Overture was $60.04 for this term. A few clicks here and there can drastically alter the ROI and survivability of a business.

If you have good server logs you can track referrals to find fraud. If you do not have good server logs there are only a couple vendors of PPC fraud detection software. Some of the larger search engines monitor the traffic, but you should also monitor your server logs if something smells fishy.
(Continues onhttp://www.search-marketing.info/search-engines/price-per-click/fraud-tools.htm)

That's why you need a system that can monitor your traffic providing crucial data such IP, Origin or Browser of the user that clicked your banner. Only with a precise report of you traffic you can analyze the kind of users you received and adjust you PPC strategy.

Due to differences in time zones and different tracking techniques up to a 10 referral difference you should contact the search engine explaining your problem.
A few things to look for to catch PPC fraud are:

Repeat clicks from a specific IP address.
Spikes in search frequency at a give time.
Abnormally high search frequency for an expensive word.
Web Marketing is everything about monitoring, Logs are the most valuable method to check your route.
ClickMeter can give you the benchmark of you WebMarketing campaign at any time.

The battle between advertisers and online search networks over the pervasiveness of click-fraud continues to grow more heated with researchers claiming rapid growth of automated ad impressions and outside observers noting an overall lack of transparency in the space.

According to a research report issued on July 19 by Click Forensics -- which markets services used by advertisers to analyze online advertisement traffic -- the average click-fraud rate for Web ads was 15.8 percent across the industry during the second quarter of 2007.

The result indicates a 14.1 percent increase in click fraud when compared to the same period last year and a 14.8 percent gain over the first quarter of this year, based on the company's numbers.

Further, Click Forensics contends that the fraud rate within pay-per-click networks run by industry leaders, including Google and Yahoo, accounted for 25.6 percent of all traffic during the second quarter, representing a 21.9 percent gain over the same timeframe in 2006 and a 19.2 percent leap in fraudulent hits compared to Q1 2007.

Contributing heavily to the significant gains in contested impressions, Click Forensics maintains, was the increased use of hijacked botnet PCs to manipulate online traffic. While not offering concrete statistics on the trend, Click Forensics' research showed that such activity roughly doubled over the second quarter. (Continues onhttp://www.infoworld.com/article/07/07/19/Click-fraud-statistics-up-for-debate_1.html)

A growing market means more traffic a wider audience and a bigger amount of valuable Data. ClickMeter Service data are useful for specific analysis about WebMarketing Campaigns.

Italian WebMarketer and Internet Consultant for global firms.www.clickmeter.com