While Facebook has been building out Messenger to handle a wide variety of functions, many of them involving monetary transactions, it’s going to focus on advertising to bring in revenue through the messaging service.
So yes, that almost certainly means more ads in your chats. David Marcus, who heads up messaging products at Facebook, told Recode in an interview yesterday:
“We’re not going to take cuts of payments. The one thing we traditionally do, and is a decent business for us, is advertising. So we’ll continue focusing on that.”