The fourth quarter of 2008 saw click fraud rates in the pay per click sector increase to 17.1 per cent, according to new figures.

This is compared with 16 per cent in the previous three months and 16.6 per cent in the last quarter of 2007, Click Forensics said – a trend that may indicate a need for marketers to make use of the relevant pay per click services to combat click fraud.

Click fraud rates also rose quarter-on-quarter on search engine content networks such as Google AdSense, while a growing proportion of overall click fraud traffic was found to come from botnets.

About 31.4 per cent of traffic emanated from botnets in the fourth quarter, compared with 27.6 per cent in the previous quarter and 22 per cent in the last three months of 2007.

"In addition, we’ve started to see old schemes like click farms re-emerge. Advertisers should pay close attention to these types of threats in their online campaigns throughout the year," warned Tom Cuthbert, president of Click Forensics.

Botnet traffic also increased quarter-on-quarter between July and September, according to Click Forensics.

News brought to you by ClickThrough – experts in SEO, Pay Per Click Services, Multilingual Search Marketing and Website Conversion Enhancement services.