I got the impression that the employees in the article were making ads. When you make ads you don't necessarily notice how exactly those ads get in front of use

I got the impression that the employees in the article were making ads. When you make ads you don't necessarily notice how exactly those ads get in front of users. When they say that the didn't know how the company made money, they probably meant that they thought it worked like other ad companies: paying websites for ad spots.