I had a conversation with a few friends about the dangers of advertising the other day, and parts of this story have been running through my mind.
The main character is a woman who used to be a marketing executive
Marketing and advertising is extremely targeted and advanced; algorithms are used to determine what a person, in certain community, based upon their purchasing patterns, will likely want to buy soon
Main character takes it upon herself to 'save' her parents and their small community from this sort of consumerism, by convincing them to vary their purchasing patterns, hoping to confuse the algorithms
Some points about authenticity
I think I may have read this story in a "hard sf" collection(?).