Facebook primarily generates revenue through advertising. Advertisers pay to display their promotional content to Facebook's users based on user data and targeted demographics. The platform allows for highly customized advertising which makes it an effective tool for businesses in reaching potential customers. In 2018, ads were responsible for 98% of Facebook's revenue according to the paper. Additionally, Facebook earns income through other services such as payment processing fees on the platform. However, the bulk of their income stems from advertising.