http://hn.vernccvbvyi5qhfzyqengccj7lkove6bjot2xhh5kajhwvidqafczrad.onion/stories/38519864
I think the difficulty lies in all the discrepancies between different storage mechanisms and normalizing the SLA there. If Dropbox is down, and your user is on Dropbox, you'll need a way to communicate that their particular "storage" is offline. The trade off is likely worth it - that is being in full control of your data and having a data export "for free" is worth it to a lot of folks.