Google, one of the largest companies in the world makes money from PPC (pay per click) advertisement. Google Adsense is the platform that provides the advertisement materials and can be used by both published and advertisers.
To make money using Adsense, you will need to sign up as a publisher, while you will be providing the content and Google will provide with the relevant ads. The system is simple: lots of publishers sing up to this program and buy advertisement; publishers will place a code to their website, where these ads will be displayed through the Adsense program. When a website user clicks on the ads, you will be credited for that click. You can receive around $0.3-$10 per click, depending on the niche of your site. A website with high traffic can make hundreds or even thousands a month.
Please keep in mind that Adsense have very strict terms of service: it is very hard to be accepted, it is forbidden to click the ads on your own site, content should be unique and high quality and lot of other restrictions. Make sure you read their TOS carefully and you are up to date with the latest changes. Although it is hard to get started with Adsense, it is one of the best ways to passively generate very good income from your website.
