Tracking users with online advertising is actually a good thing for economic efficiency. People tend to see more relevant products, and are able to allocate their resources to products that better meet their needs. The best ads aren't lying to people.
How is that true if the "best" ads are still paid for by companies who might not sell the best stuff?
Ads just try to drive up sales. This is something we don't need given current energy/climate issues.
There are better ways of bringing supply and demand together. Several decades ago we had yellow pages, and they worked fine. I'm sure in the internet age we can come up with an even better system that doesn't involve user tracking and/or distracting ads.
Many people don’t care about optimizing for buying the best of its kind, they are just interested in something interesting/useful. Ads relevant to interests is more efficient than ads not relevant to interests.
Only if your measure of efficiency is more things bought and sold. An efficient economy would do the same work with the fewest goods moved the shortest distance possible. What we have is the opposite of that. You go to the store today and there's a plastic can opener that will break in 2 years and came from parts sourced half a world away instead of the metal one your grandfather has been using for the past 75 years and was stamped in a building downtown using steel also smelted downtown with ore from within the region.
I.e., people buy stuff they wouldn't buy if they got honest information.
It works against the main argument in favor of the free market: not the best product wins, but the one with the biggest advertising budget.