how does google adsense track clicks on ads, is it only through IP addresses...

[thyagu]

...from which the clicks originate? how does adsense track fraud clicks. Is it only through IP addresses or something else like MAC addresses?

[Karel B]

IP address, cpu serial, mac adres, cookies, browserversion, browserhistory, ... Who knows what it all is that they use. But if you click it falsely, they will know, and will end your account.http://www.icantinternet.org

[dreamydonkey.com]

They track through Cache stored in you computer,IP addresses et,Browsing history.They also check CTR and if it goes high you come under suspicion