How money offering websites earn money to pay others?

Tweet

Where is money on the internet. Till now I find only Google earns money through advertisements. Google receives money from the advertisers, they pay a part to the publishers. But other websites where there are no Google advertisements; how will those websites ear. Who pays them? Why they pay them? For example article writing websites pay money for freelancers. Once your article is approved and published, they pay you as per terms. Then they populate the article on the internet. Say they get a huge traffic. I still did not understand how the website that populate your article earn money. I am not sure whether I understand internet and it's potential well. Can any one answer these unanswered questions