[yorwba]

I think ads are useless when you want to decide within a product category ("Which 3D printer should I buy?") but they can help you become aware of it in the first place ("There are affordable 3D printers now? Maybe I should get one.")

Unfortunately the majority of the consumer market revolves around a few common products and so most ads are about shifting revenue between functionally identical brands.

But I do occasionally see ads for relatively obscure stuff that might cause such an "I didn't know that existed." experience for other people. (I'm apparently hard to target.) For example https://news.ycombinator.com/from?site=viva64.com are essentially ads, but they are still interesting to read, and afterwards you might be in the market for a code analysis tool.