One of the things that surprised me about the Chitika advertising program was a statement in its list of frequently-asked questions. Specifically, the answer to question 10 about the difference between audited and unaudited revenue. The answer includes this phrase: “In the audit process we remove any invalid clicks such as … clicks from countries such as China and India”. That statement itself doesn't really surprise me, but the fact that they've stated it so boldly for everyone to see does.
The fact that certain countries like India and China are breeding grounds for click fraud has been well-documented before. AdWords advertisers can specifically exclude these and other countries from their advertising campaigns by using geo-targeting to specify which specific countries (and/or languages) they want their ads to target. But AdSense publishers have no such facility. They have to use server-side scripting to decide to display or not display advertisements based on the visitor's IP address.
Unlike what Chitika admits, we don't know what algorithms Google uses internally to detect invalid clicks. I've often wondered if Google has a “developing country discount” or some other flag that causes a click from such a country to be treated differently by the fraud detection algorithms. This is pure speculation on my part, of course, but I would imagine that the geographic location of the clicker's IP address (which can be determined from various geocoding databases, although if the clicker is using a proxy it only gives you the location of the proxy computer) plays some part.
There is a warning here for AdSense publishers. If you're developing a site that is aimed or popular with visitors from developing countries, you must be extra vigilant about click fraud. Please read my previous blog entry Proactively possible AdSense click fraud to avoid getting kicked out of AdSense.
That said, many people in the developing world who can build themselves quality blogs/sites have an interesting advantage over others in the sense that the payouts from AdSense make a much bigger difference to them in terms of overall income. Several of my readers are from that area and have built such sites, check out the reader-built sites section of my reader resources page.
uthor of Make Easy Money with Google, a real (printed!) introductory AdSense book for non-technical people, available at all fine bookstores. Be sure to download the free sample chapter for more information about the book.