There is a new topic titled “The Behavior Behind Users Clicking On Google Adsense Ads” on the WebmasterWorld discussion forum the I recommend checking out. The discussion covers the rationale behind internet users decision making process involved in clicking on a Google Ad. Some of the possible explanations are below:

1. “Compelling on topic or relevant supplemental information”
2. “They don’t know it’s an ad (well “blended”)”
3. “They know it’s an ad but want to get the hell out (MFA)”
4. “Just boredom”
5. “because they are basically stoopid!”
6. “they want to buy something the ad represents”
7. ” If they get something for FREE”
8. “If they find the caption of the ad attractive”
9. “If they trust your site they feel the ads are also genuine.”
10. “Plain old laziness”
11. By “mistake”