1 the application software that is designed by using an auto click program or a special click advertisement.
2 hire cheap labor or induce others to click on advertising links.
3 publishers manually click ads on their pages.
4 publishers to operate their own web pages in this way: the interaction between the user and the site lead to inadvertent ad clicks.
5 was released to flow to the site can be purchased false extra traffic to their site to bring, including extra click on ads.
6 advertisers manually click on ads for their competitors.
7 publishers who have suffered retaliation from their competitors or other malicious agents.
8 various types of unconscious clicks, such as a two click or a customer who is confused and unconscious of non malicious ad clicks.
9 technical problems, system execution errors, and the double statistical errors caused by the collaborative activities between Google.com and its members.
10 Adsebse publisher of multiple accounts: some Adsense publishers illegally open new accounts with different names and false identities; all clicks from these illegal accounts are considered invalid.