For instance, I follow King Arthur Flour for their scrumptious baking recipes. It'd be great to be able to go straight to their online store to purchase some of their harder to find ingredients like Boiled Cider.
One thing I hope they do is make it so everybody can get in on it. Say you want to be able to sell prints of your great photos, how awesome would it be to have a built in way for customers to do so? Or have a brewery and want to sell some t-shirts?
That said... will this taint the instagram experience? Youtube feels increasingly optimized for profit-making and seems be crowding out some of the more "just-for-fun" type projects. If too much of a social media site focus on profit it becomes just another mall and less of a social setting.