Interesting. Most of the people I know on it post less than on Facebook and there's a much higher ratio of other photos to selfies/screenshots compared to other social networks. I only post a couple times a month when I feel like I have a photo worth posting.

As more people move over from mainline Facebook and Facebook adds more Facebooky features to Instagram, I expect it will get less useful for this. There's also not a lot of timeline control, so you do end up with situations where someone goes on a trip and suddenly you have 20 posts in a row from a single person at Disneyland.

I suppose if you're using it as an all-purpose social network and trying to maintain a persona, the inability to post anything other than pictures applies a lot of pressure to always have exciting new pictures to post.