Instagram does two things. Firstly, and most obviously, it takes photos, sticks a filter on them, and uploads. But it also has a social aspect to it; it gives you a single, very simple view of the photos of your friends - a flat list in reverse upload order.
When I first started using Instagram, I just turned on the 'post to flickr' option for all of my uploads and didn't think about it again. But that stream has a certain fascination to it - photos are uploaded one at a time, in the expectation that people will look at them very soon, and they're fleeting - there's no homepage for your past photos. You link to them or they go. People only upload things that they think people want to look at.
Combine this with an app like Carousel so that I don't have to keep waking up the phone to see things, and I've started to quite like the ambient pictures that it gives me.
I haven't decided if any of this is Meaningful yet, however. These photos are interestingly ephemeral. I'm not ready to decide if transience is a useful property, but I keep coming back to Jason Scott:
[..] if someone gives you an amazing Moon Laser and the Moon Laser lets you put words on the side of the moon, the fact that the Moon Laser’s effects wear off after a day or so isn’t that big a deal, and really, whatever you probably put on the side of the Moon with your Moon Laser is probably pretty shallow stuff along the lines of “WOW THIS IS COOL” and “FUCK MARS”. (Again, to belabor, a historian or anthropologist might be into what people, given their Moon Laser, chose to write, but that’s not your problem).
To hedge against this, I still upload all of mine to Flickr (except when I forget to press the button grr defaults) and I have the phone set up to store all the pre-filtered high-quality versions of the photographs (there's a minor issue here that instagrammed photos have crap exif - this may bite me later. We will see).
Anyway, there's nothing inherent to Instagram-the-application about any of this. This is just the model that the software encourages. As an experiment, I threw together something that I've called (for now) flickrgram. It emulates a similar thing for your flickr photostream - stuff your contacts have posted, in reverse-uploaded order, with a tiny bit of metadata wrapped round it. It's formatted for iPhone, because I like the portability, but scale it up a bit and it's a perfectly decent desktop interface (I'm using high-resolution images for the retina display, so it still looks good).
And here's the conclusion I, and some people I know, have come to -- it doesn't work as well, because people don't use Flickr the same way as they use Instagram. This isn't entirely unexpected -- several people have mentioned that they put photos into Flickr more for archive and storage than for sharing. I know plenty of people who will upload massive batches of photos (hundreds at once), entirely swamping everyone else. (Luckily, the API call I'm using to populate flickrgram returns at most 5 photos per user, so I'm defended against this. But only by accident.)
The interesting thing to me is that these models -- "shoeboxing" verses Instaagram-style "lifestreaming" -- are two entirely different usage models for a photo sharing site. Flickr was built for the streaming case (it's got a photostream as the main thing you see) but recently the shoeboxing is rather swamping the streaming, and the two models just can't coexist in the same contacts list - the uploads of the shoeboxers will swamp the incoming streams of people who just want to follow streamers. Instagram, on the other hand, by utterly ignoring the needs of shoeboxers, has been able to build a much better streaming experience.
It reminds me of Twitter, where the same thing has happened. The high-volume broadcast / at-reply people drown out the ambient "eating a sandwich" group of people that I quite liked getting the updates of.
Two things interest me about this. Firstly, is this 'streaming only' interface convention something that's going to hurt the Instagram streamers in the future? Are they going to realise in a few years that they've not built up any meaningful history in this service? When they want a photo they remember taking, and can't get it, will there be pain? Or will no-one care?
The other question is, can you get any money out of streamers? Shoeboxers want reliably stored photos, safe URLs, lots of upload bandwidth, all things you can charge money for. They can't easily drift between services, because they have all their data in this one. Streamers don't care. They haven't got any history, and as long as the streaming app will push into facebook, who cares what the backend is? They'll change apps just because the new one has a better filter.
Maybe the streaming experience that Flickr provides is as good as you can get it, because you have to pander to people who want to do archive, or you can't make proper money.
Anyway. go play with flickrgram.