I was using the Internet at a time when people took it being non-commercial completely seriously. You never saw ads because, as a community, we had decided that ads were not allowed. It was completely decentralized, so you might be running your own server, but if you put an ad on your server other people would get mad at you for it. This was pre-WWW and then a bit of the early days of the WWW.

Then there was a period where ads, commerce, shopping, etc. were possible and permitted. But, that was still the minority of things. There were thousands of web pages full of mythology and folklore for example, that people had just put up because that was something they were interested in. Running a web page cost you next to nothing, so there was no need to put ads on it. You could use Yahoo to find those sites, and I guess Yahoo was commercial by that point, but if it had ads they were small and unobtrusive.

Over time, things got more and more commercial. You saw ads more and more often. But, at least then it was ads on static content, or ads on a forum or something. It wasn't an infinite algorithmically-generated feed optimized to keep you engaged.

There was a lot to like about that super early non-commercial Internet. But, I don't think that was the peak moment though. Some ads and early for-profit services made it better. I think the thing that really wrecked it was the lack of competition. When there are 100 commercial services fighting over your attention, they can't collude, you can boycott one, etc. When there are 5, you basically have to accept whatever they give you.

It's not figuring out but just waiting until there are more non-nerds moving in that new market and then start monetizing as the market reaches critical mass for their particular niche.