AdSense is an advertising service from Google which allows website publishers to display adverts on their site and earn money when they are viewed or clicked.
Adsense generally matches advertisements to websites according to their industry - for example, a mountain biking blog using AdSense would display adverts related to mountain biking or cycling.
Sites with AdSense make money on a per-click or per-impression basis, but each click or impression generally gains a very little revenue. That's why AdSense sites with the sole purpose of making money (known as made for AdSense sites) make it a priority to gain as much traffic as possible to their content to maximise clicks and impressions.
Adsense is free to use on any site - you simply have to sign up and copy and paste a code snippet. The adverts are shown are controlled controlled by Google but the website owner can choose how to display them. Some of the most common ways to display are:
Ads can also be displayed in different ways such as simple text or rich media.
Verified publishers can also display ads in other ways including in apps or video content.
Find out more about displaying ads on your website with AdSense.