We are not even off the starting blocks of cloud computing! Major EDA vendors wont flock early. Security, license are some of the issues that come into mind immediately. If I were to analyse a gate-level netlist of a design from XYZ company using tool ABC. XYZ should have a licensing agreement with ABC, should need a secure network (like https?) to send their netlist across to the cloud, run the job (how many seconds or hours or days?), get the results back (in a file or display on screen?), debug if necessary etc. I can roll off stumbling blocks just with on-top-of-my-head thoughts.
I wish major EDA vendors like Mentor and Cadence offers cloud computing with their tools like Mentor Hyperlynx for simulation and similar tools. If I can interface my Altium AD10 schematic and layout to Mentor Hyperlynx for SI analysis of high speed designs on cloud computing, it will be very helpful.
As several commenters have pointed out, a cheap flash drive or portable hard drive solves the backup and file storage needs of most of us. Pay-as-you-go cloud storage just doesn't offer much of a value proposition (free cloud storage is a different story).
But what about true cloud computing? That won't likely be free. A very powerful desktop PC can be built for rather low cost and I will never need to pay a rental fee to use it. Pay-as-you-go cloud computing isn't likely to offer much of a value proposition either.
More on Apple
Apple’s belief is clearly that users will not and should not care how the cloud actually works.
Some relevant links that I got today
This mentions about the 'super-fast connectivity and monitor+keyboard' paradigm that I mentioned. The other link is the set of white papers on cloud computing - http://www.computerworld.com/s/whitepapers/topic/158/Cloud+Computing/1
As far as a service provider in a cloud system, I think Steam has done well so far. A person has a library of options available to them and download that option at their convenience. And the items that they have downloaded to their account are available at any PC that has the Steam program available. Blizzard has done something similar with games that are purchased. Once registered, said game can be re-downloaded if the data is corrupted on the individuals PC, given the appropriate log-in info.