There's plenty being written about Instagram at the moment as we lay bets on its continuing success, but amongst it all what I've learnt from the service is how primitive our requirements of technology remain. I mean this in the best possible sense: there is something reassuringly human and simple that is key to the service's success.
Compare it with Flickr which is great in its own way (although it seems to have been stalled for a good few years now) and the parred down basics of its success become clear. Flickr offers tonnes of functionality from mapping images to slideshows, multiple scaling options, privacy settings and uploader tools. Instagram has a few simple filters and the sharing infrastructure of Twitter, with simple options to extend beyond the network into your other social destinations on an image-by-image basis. So, ease of use and real time social sharing are the key to the success of a service that unlocks our intrinsic urge to share in a manner that avoids the clanging premeditation of the worst Tweets and status updates.
What has become clearer since Instagram released its API and the fans and entrepreneurs (or likely, both combined in the best cases) have gone to work is the irresistible pull towards the analogue world that these modest social time capsules inspire. The filters may be a re-presentation of the analogue effect but there's a very tangible physical allure that has manifested great service initiatives like Instaprint - a location based photo booth that prints out Instagram images based on hashtags relevant to localised activity - and Stickygram - which promises to deliver your Instagram images as fridge magnets. There's also Instagoodies which creates sticker books from your Instagram pics, Teenytile that makes 2" ceramic tiles from your feed and all manner of other services for printing, framing and displaying pictures in realworld settings.
Somehow this flurry of 'analogue' (I know its not strictly correct) activity somehow embodies the appeal of the service perfectly. Of course, I could be missing the point and the API extension that really nails the Instagram phenomenon might just be this.
PS. Special mention to Postagram which I just came across after hitting 'Publish' - postcards of your Instagram pics, of course.