I have noticed some strange high CTR on one of my sites.. I was worried that someone might have sabotaged me.. Luckily after getting the reply from the Adsense team, I felt more relieved now.. phew .. Here is the response from them : - Thank you for letting us know about this situation. Rest assured that we have noted your input and we will continue to monitor the situation closely. I understand that you are concerned about keeping your account in good standing and that you would like more information about the recent activity on your account. However, because we have a need to protect our proprietary detection systems, we are unable to provide you with any details about your account activity. I also realise that you might have questions about what Google is doing to prevent invalid click activity. You should know that our specialists carefully monitor clicks and impressions on Google ads in order to protect your interests as well as those of our advertisers. To do this, we use both automated systems and human reviews, analysing all ad clicks for any invalid click activity that may artificially drive up an advertiser's costs or a publisher's earnings. Please note that according to our Terms and Conditions, Google will use its sole discretion when determining instances of invalid clicks. Lastly, I wanted to let you know that in the future, we may adjust your payment for any days during which invalid clicks occurred. This helps us protect the integrity of the AdSense programme and properly credit advertisers for any invalid activity. Thank you for your cooperation. We look forward to working with you in the future. For additional questions, I'd encourage you to visit the AdSense Help Centre ( http://www.google.com/adsense_help ), our complete resource centre for all AdSense topics. Alternatively, feel free to post your question on the forum just for AdSense publishers: the AdSense Help Group ( http://groups.google.com/group/adsense-help ). Sincerely, Lucy The Google AdSense Team