I'm not sure that Facebook using Instagram as a way to funnel people back to Facebook is a great strategy. Companies need to be willing to cannibalize themselves or someone will do it for them. I don't know if Zuck had the foresight at the time, but Instagram has obviously been an amazing hedge against apps like Snapchat. People like Instagram and Snapchat partly because they are less formal than Facebook, most users…
Nit, this strategy seems to have failed—alternatively they’re just changing instagram to be more like facebook (ads, no timeline control, messaging and stories).