Have you ever checked your reports and noticed that you have clicks reported, but no revenue? We'd like to explain why this may happen, as we frequently receive emails and questions on our Help Forum about this issue. What you're seeing may be due to one of the following:
Allowed Sites setup
The Allowed Sites feature allows you to specify a list of sites where ads from your account may be displayed. If you're using this feature, you'll need to make sure that you've listed all sites where you'd like to display your AdSense ad code.
To check if this is the case, log into your account and visit the 'Allowed Sites' page under your AdSense Setup tab. If the radio button 'Allow any site to show ads for my account ' is populated, you're not being affected by this issue, and you should continue to #2 below. However, if 'Only allow certain sites to show ads for my account' is populated, review the list of sites in the box below -- are all the sites you own listed in this box? If the answer is 'no', you won't be credited for clicks on the missing sites. Please be sure to add all of the sites where you'd like to display your AdSense ad code.
We've noticed some confusion among publishers who have entered the sites of advertisers they'd like to see on their pages into the Allowed Sites list. Please know that this is not the case, as it's not possible to request ads for a particular page - the sites you enter into this box can only be sites where your ads can be placed.
Invalid clicks
It's possible that you have some clicks that our monitoring system has considered to be invalid. As we've mentioned before, we monitor all clicks and impressions on Google ads for any activity that may artificially drive up an advertiser's costs or a publisher's earnings. Any clicks that our system considers invalid will still appear on your 'Overview' page, under the Reports tab. However, because our advertisers aren't charged for these clicks and impressions, we won't show the earnings for this activity. If you're concerned about suspicious activity in your account, we recommend reviewing your site's logs and letting us know about the situation.
Rest assured that AdSense accounts are properly credited for all clicks and impressions we consider to be valid. We'll post your finalized earnings for a given month on your 'Payment History' page during the first week of the following month. For more information about invalid clicks, please review our Help Center.
The important Factor on Google Adsense is Clicks, This will help you understand the difference on Clicks.
Invalid clicks are clicks for which we decide not to charge our AdWords advertisers, since they may artificially drive up advertiser cost or publisher revenue. These include extraneous clicks without any value to the advertiser, such as the second click of a double-click. They also include many other types of clicks that we've determined aren't motivated by genuine user interest.
Invalid click activity consists of any clicks or impressions that may artificially inflate an advertiser's costs or a publisher's earnings, and for which we decide not to charge the advertiser. This includes, but is not limited to, clicks or impressions generated by a publisher clicking on his own ads, a publisher encouraging clicks on his ads, automated clicking tools or traffic sources, robots, or other deceptive software
"Invalid clicks" are often confused with "clicking on your own ads". However, we'd like to stress that invalid clicks are generally any clicks that artificially inflate advertiser cost or publisher revenue, regardless of their source.
Click fraud is a subset of invalid clicks that are generated with malicious or fraudulent intent -- in other words, clicks that are intended to drive up advertiser cost or publisher revenue artificially. Sources for these clicks include, but are not limited to:
A publisher clicking on his own ads, or encouraging clicks on his ads
Users or family members clicking to support the site / publisher
Third-party programs with user incentives, such as paid-to-click services and click-exchanges
Automated clicking tools, robots, or other deceptive software
The same principles above apply to ad impressions and conversions as well. Some sources of invalid impressions include, but are not limited to:
Excessive page refreshes, generated either manually or automatically
Third-party programs with user incentives, such as paid-to-surf or auto-surf programs
Third-party programs for purchasing fixed amounts of traffic, e.g. "$10 for 1,000 page views"