Obviously this doesn't apply to classified ads or their electronic equivalents. But what we normally mean by advertising, where people are paid vast sums of money to think very, very hard about how to manipulate you to hand over money for shit you don't need, is vomit-inducing. Billboards are even worse because they deface and degrade the public landscape, and ugly landscapes can contribute to depression, anxiety, irrational anger, and other problems. They are as bad as littering.
What has made people think this is ok?