Attention is one of the most valuable resources that human beings own. It is the gateway to control behaviour. Therefore, the attention economy seeks to control and manage this function. Today exists a new currency exchange: the consumption time in the platforms. Within information and digital society, the attention becomes a key to understand the social media business. Consequently, social media articulate four different mechanisms to capture this resource: notifications, messages and posts, Fear of missing out, and Likes and rewards. Likewise, comprehending its function is the way to understand how the social media make a profit from it. The attention economy shows that the attention is an important but scarce resource to cement the social media system. This chapter discusses the main neuropsychological characteristics of attention and their implication in social media mechanisms.