alt Hacker NewsThose ads were the only way to actually know what software and hardware was available to buy, including information related to "open source of the day", shareware, PD,...
Access to BBS was super expensive unless you were lucky to afford a modem, and live on local call distance.
European magazine like Computer Shopper were of similar size and ads ratio.
Ads that are well target aren't jarring. They are just part of the magazine.
I remember reading ads about a specific make of vacuum pumps next to an article with experiments which used them.
Today's ads are so obtrusive because you get toilet seat ads next to an article about general relativity.