If I'm going to spend time creating amazing marketing content, why would I post it and have it disappear in a few days? If I follow Target, they can offer me toothpaste this week and cheap sandals the next. If they interest me as a brand, I will follow them to see what this week's offer is. We sell a specific product that people want when they want it. On the surface you might say, well, if I keep hitting them with special offers and other photo ideas on something like SnapChat, they might eventually decide to buy. The problem with the logic is that if they are not in the market for photographs now, they will most likely decide to unfollow you long before they decide to do so.