Earlier quoted context omitted.
How is online advertising not useful? It's directly greasing the gears of the economy, matching up potential customers with businesses in a reasonably intelligent way. Yeah, sure, it's not saving the world from climate change or something, but it's clearly facilitating economic activity, and also helps keep a number of very useful products free. Seems pretty useful to our society to me.
Don’t you think a catalog would do a better job of matching up consumers to products? Given our environmental situation, is it really ethical to “convince” people that they need some new thing that they previously didn’t know about or want? Re: keeping stuff free, that’s still pretty convincing and it’s mostly what keeps me going as I work on the great google ad machine. It seems like a massive social good for sites…
As for the environmental situation, it is unfortunate. But I do believe that the only realistic way out of the climate crisis without a collapse-level drop in standard of living (read: starvation) is technological innovation, a process that seems to be aided a lot by a healthy economy (which results in stable livelihoods, etc). So I'd say if anything there's a moral imperative to keep the economy as healthy and productive as possible.