Yes, I had some pages on geocities around 1996/97 and to the best of my memory they had no ads. I must have stopped using the site entirely by the point they got added.

edit: Wikipedia claims that happened in May 1997.

That's exactly right. They were REALLY chill in the early days: "The only code that we require to be on all of your html pages is a reference back to GeoCities. This can be a reference to the main Neighborhood page that you reside in, or to the GeoCities Home Page. Please see the FTP Procedures Page for the preferred source code." from https://web.archive.org/web/19961220170537/http://www.geocit...

The other rules are actually pretty cool, too. Zero commercial use allowed. This probably singlehandedly ensured the most diverse and interesting content.

And in order to find those neighbors in my neighborhood, we started web rings... Sites I liked were added to mine. My friends added me to theirs. Next thing you know we have curated journeys through web design - graphics - music - literature - art - trade skills - DIY - and well... let's just say they like four channels.