Internet is great medium to interact with people and promote there product these increase the sale of product. Number items are sold over internet everyday and less in offline market,
online market like e-commerce is a big platform for sales.
For these sales industry required to promote these product, to promote internet is great as it has huge amount of traffic to gather audience.
Advertising plays a central role in the availability of many internet products Google, Facebook, Twitter, etc. Without the ability to advertise, these services will charging a fee to use their service. Overall internet usage will drop and accessibility of information.
Without alluring advertisements, consumers would buy less. They would also be much less informed and make more inefficient purchases. This in turn would result in less innovation as people rely on what they know, not the new information gain from advertisements. The economy would in turn contract, with multipliers exacerbating permanently lower consumption. It would be decades before we would return to the level of economic output we experience now.
The bright side is that people would likely save more and discard less. This would conceivably help the environment.
