Peggy Dean at The Pigeon Letters:
As you probably know, Instagram's algorithm is a nearly unsolvable puzzle and right when we think we've solved it, it changes again. Staying in the loop is harder than ever, as many changes are no longer being regularly announced on Instagram's blog, but rather just being updated in a buried folder in their Help Center. There's some good and bad with these changes. How people interpret these changes is to each their own.
I generally tend to use Instagram as a personal tool for insipiration and fun. I have, however, casually wondered why some posts seem to reach more followers and deliver more engagement than others, this is fascinating.