I absolutely love this concept, and what a thoughtful way to present it, too. I’m eager to see this concept on other platforms as well (I believe there’s one for Twitter as well— @pmarca would be my go-to lookup!)
How are you handling private feeds? Are you informing the end user that there are X accounts that they don’t get access to?
Also — you’ve put a lot of thought into an Instagram sidekick — what do you have planned next? Would you explore more with the Instagram API, or start investigating other platforms like Twitter, Tumblr, and Vine?