From Federico Viticci, on MacStories:
You just used five apps and created four copies of a file (two of them are iOS Camera Roll + Photo Stream) to annotate a photo. Lather, rinse, repeat for note taking, PDF reading, electronic bill management, and assembling that nice slideshow of your vacation in Italy.
Yes, I love a lot of things about Apple, but it’s not a blind love.
File sharing between apps on iOS still needs a LOT of work. Meanwhile, it’s incredibly annoying, benefits notwithstanding.