The real strength of Dropbox comes from the ecosystem of apps that use dropbox to store data. It is hard for newcomers to challenge that network effect. But competitors like Tonido are doing interesting stuff by focusing on the security, privacy and the private aspects of owning your own cloud. If they are able to change the narrative from utility to trust and security then newcomers have a fighting chance.
Finally it comes to what wins the customers: Trust or Utility or the Balanced of Both.
Tons of mobile apps do this. 1password is probably the best example, but just the other day I decided I wanted to be able to view a Sketchup file on my phone and the app I found ( https://itunes.apple.com/us/app/sightspace-free-d/id56721967... ) had the option to load files from Dropbox.
My comic book reader uses Dropbox to sync, my todo program uses Dropbox to read my todo.txt, I use Dropsync to do 2-way syncing between a directory on my phone and my computers mainly so I can drop reciepts + other PDFs into a directory on my computer and get them from my phone, tablet or other PCs.
I could go and replace all of these with another tool, but I would have to have a compelling reason to do so and would probably have to find some new apps (or the apps I use would have to integrate a new service)
Does it work offline at all? I took a brief look at the API, and it seemed like any time you wanted to make a change to the data it needed to talk to the server.
While i condemn the violence, i have hard time justifying uber as a new revolution or advancement of technology.
Medallion owners pay close to 1.0 M $ to get the Taxi license from the city (NY) and they are not doing that for charity. If a new middlemen like Uber try to take the market without paying single dime it is bound to cause issues who have played by rules and invested significant money to acquire the license.
Uber simply tries to aggregate the demand side and demand concessions from the supply side to get the leads. Portraying Uber as egalitarian is wrong in so many levels.
Finally it comes to what wins the customers: Trust or Utility or the Balanced of Both.