This study sheds light on several key issues faced by marketers and advertisers. $83 billion is a big number, but it is not hard to see. Here is a back of the envelope type explanation.
10000 Adwords clicks – About $10,000. If the conversion is 1%, it translates to 100 customers.
If you increase conversion by a small 2%, you will acquire 300 customers.
If you had to acquire 300 customers at 1% conversion rate, you will spend $30,000! So, increasing engagement, even by a small percentage, could have a significant impact on the business!