One good quarter does not make a trend, but there is a glimmer of hope in the fight against click fraud (fake clicks that can nevertheless cost advertisers money). Click Forensics is reporting that the overall click fraud rate was down half a percentage point in the first quarter to 16.3 percent. Although that is still higher than the rate was a year ago, it could be an indication that Google’s and Yahoo’s efforts to filter out bad clicks on search and contextual ads and improve the overall quality of those ads is starting to have an effect.

When you look at the click fraud rate on their respective content networks where the worst offenses occur, AdSense and the Yahoo Publisher Network, the click fraud rate there also dipped slightly to 27.8 percent from 28.3 percent in the fourth quarter. That is still nearly a third of all clicks and needs to seriously go down further.

Perhaps this year the overall click fraud rate can be held steady instead of rising 15 percent, as it did in 2007.