I hear this a lot but there was just a very small early period where a few enthusiasts were on bulletin boards (and definitely not "tons of sites").
As soon as the web was mainstream and had any appreciable amount of content, there were ads right alongside.
> Prior to the disestablishment 1995 commercial traffic on the Internet in the United States was limited by law, and prior to 1988 for the most part strictly forbidden, with the exception of traffic with research and defense aims.
Also the first cross-network banner ad ran in October 1994: https://hbr.org/2013/02/stop-selling-ads-and-do-someth
I hear this a lot but there was just a very small early period where a few enthusiasts were on bulletin boards (and definitely not "tons of sites").
As soon as the web was mainstream and had any appreciable amount of content, there were ads right alongside.