Users viewing ads will be rewarded with BATs. BATs can be used for premium content or services on the Brave platform.
Attention is measured as users view ads and content in the browser’s active tab in real time. The Attention Value for the ad will be calculated based on incremental duration and pixels in view in proportion to relevant content, prior to any direct engagement with the ad.
Mobile advertising results in as much as $23 per month in data charges on the average user’s data plan, slow page loads, and as much as 21% less battery life. Meanwhile, hundreds of millions of users have installed Ad blocker. BATs allows users to contribute to their favorite Publishers while removing invasive advertisements. The Brave browser blocks Computer cookies by default, which can reside in Random Access Memory even after computers are restarted. These cookies and trackers have the capability of monitoring users' Web traffic to see which sites were visited. Personal Data is then sold to advertisers. [✔]
BAT was created with Privacy of its users in mind. Facebook has an embedded 'Like' button which many 3rd party websites utilize which tracks user activity. This allows Facebook to sell highly targeted ads based on past web traffic. 
Initial Coin Offering
There were 500M tokens created for users and the developer team, 350M in reserve and 1 Billion to sell during the ICO.