From the Flickr camera finder, a graph showing the drop-off in the iPhone 3G as a source of images. Note for a while that the 3GS - the next newer model - paralleled but never exceeded the number of members uploading from the 3G, while the 4 exhibited a delayed but steady rise to where it's becoming the most popular model. It would appear that the 3G is being rapidly replaced in the Flickr user population.

Note that this data doesn't tell us anything about the larger population of smartphone users (and the subset of picture uploaders) - it's possible that images from these Apple and non-Apple phones are being uploaded as often, but to other services, or that if you don't own an Apple smartphone, you just don't upload to Flickr.

Still, as a way to track the death of a product, it's an interesting indicator. Just goes to show that there's lots of opportunities for web-services to exploit the informating capabilities of technology.

Next: find out where all those discarded smartphones are going (China? Poorer populations who just haven't discovered Flickr yet?) and look for evidence of use in corresponding web services (Kaixin/QQ? Myspace?)