Look, It's the question of the internet except the answer is specific to Adsense. YOU as a blogger or website owner can make money by monetizing your site. That means putting ads that is paid for by a company that has paid for google adwords. Google charges companies to place banners on websites and hopes a user clicks on them. Adsense is free to use and pays out once a month after it reaches over $100. Once you recieve your payout your balance starts over from $0 again.