I talked with a professor of advertising to make sense of what this means for all of us who use those social media platforms.

WhatsApp says that users will start seeing ads in parts of the app, as owner Meta Platforms moves to cultivate a new revenue stream by tapping the billions of people that use the messaging service.

The days of “No ads! No games! No gimmicks!” are over. That was the slogan coined by one of the founders of WhatsApp, Brian Acton, which the other founder of the messaging app, Jan Koum, used to keep taped to his desk on a sticky note.