[vmception]

Curiosity. Intrigue. Boredom - well not necessarily, it is a form of entertainment for the instagram culture.

There is also silly user experience on instagram where you can share photos from a private profile to your friend but your friend can't see it at all unless they request to follow the profile too. Some content types get this behavior, more like animals, tropical landscape photography. Sometimes women/models, but thats more of a personal fawning.