Thomas J. Watson, chairman and CEO of IBM from 1914 to 1956, allegedly once said (and I doubt he ever did) the following.
"I think there is a world market for maybe five computers"
It was claimed that he said so in 1943.
And indeed, 70 years later he is finally right. Most of us now use our home computers, and more so our mobile devices to access, use and depend on the five big computers everyone needs.
The big clouds, large collections of small computers forming one big computer each, at least one of which we each also use every day; they are the computers of the 21st century.
They are Apple, Google, Amazon, Microsoft, and Facebook.
I certainly have an Apple account, a Google account, an Amazon account and a Microsoft account. And I have associated devices and home computers that interact with those four clouds to synchronise emails, address books, calendars and files.
I think only my small ARM Linux box does not know at least one cloud login for one of the big four.
Google even offer an operating system that consists basically just of a browser and acts as a terminal only to Google's cloud applications and the Internet.
And Microsoft Windows 8 allows logins with local accounts as well as with "Microsoft accounts" that are cloud accounts.
Each cloud owner tries to sell devices that can mostly and mainly be used to access the cloud. It is difficult to exchange data between clouds or synchronise calendars or address books.
Applications now run either on the (or rather a) cloud or must be digitally signed by the cloud owner to run on the new access devices like the iPhone or tablets.
Old-style (or "desktop") applications run unsigned, but phone and tablet applications run only on permitted devices in the permitted way. This makes the environment very secure for the user. But it also takes away users' freedoms in ways that copyrighted software never has before.