Adsense is still a favorite and the king Pay Per Click (PPC) advertising network for publishers, but often we are careless in "use" our adsense account. Reckless here in the sense put your ad code on websites that violate the Terms οf Service (smelly porn sites for example) or clicking your own ads or get someone else to click on ads to us because google will know about it. It is said that Google has technology capable of tracking the mac address of a computer via a cookie expiration time until 2023, but the google stating that the cookie expiration is now derived manjadi only 18 months (source), so if one time we click our own ads using the computer the same although with different IP and the computer has been re-installed the google still keep our computer data through the mac address mac address which is stored in hardware and will not change even if the computer is lost or re-installed.
As one publisher who had experienced a nightmare banned by google, I was warned to NEVER CLICK IKLAN ADSENSE-ONCE YOU OWN OR get someone else to ADSENSE ADVERTISING CLICKING FOR YOU.