The economics of attention refers to the scarcity of attention. The basic idea is that attention is valuable because it is scarce. Sellers (such as advertisers) will pay to get peoples' attention.
Communication requires a transmitter and a receiver of information. The internet has lowered the cost of transmitting information to practically zero. Anyone can set up a web site or send out a spam email. That's transmitting information.
But transmitting information is no use unless someone pays attention to it. People have a limited amount of attention. They can usually only pay attention to one thing at a time. If you have someone's attention - such as by televising a beauty pageant or a football game - people will pay you to share that attention.
The economics of attention is the reason why the advertising industry exists.
The term comes from economist Herbert Simon: "a wealth of information creates a poverty of attention."
