How many click frauds are detected proactively vs. reactively? The numbers are rising... Google says invalid click is 0.02% of clicks.

Invalid clicks (a term used by Google) mean all the clicks yielded by online ads, a percentage of which is deemed "invalid." Nonetheless, not all clicks are fraudulent. Less than 10 percent of all clicks are considered invalid.

"The overall rate can fluctuate. We've said before that this is in the single digits and want to clarify that this means it's from one to nine percent. It's not zero, but these are lower bounds," said Shuman Ghosemajumder, business product manager for trust & safety at Google.

When asked why release the figure just now, when many have wanted it for literally years? Ghosemajumde explained:

"We've been working to be more transparent and informative on the issues related to click fraud. Recently, this metric has been something advertisers have specifically asked for and we agree that is useful in describing the scope of the problem. Further, it is something we measure and use to monitor the performance of our click fraud detection systems."