"Space is big," said Douglas Adams. "You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space..."
And so on. The point being that, not only is it big, but that it's so big that 'big' doesn't quite cover it. The scale and numbers involved become so massive that they start to lose meaning - and what's true for Space is also true for the Cloud; this distributed network of storage and processing power is so large that we can't really conceive it fully. Saying that Twitter users have been sending more than 200 million tweets every day since this time last year may sound impressive, but functionally the figures are meaningless. We need some other way to express the sheer scale of this digital enterprise, which increasingly blankets our virtual lives and stores our personal data in places we've never heard of.
We need to say that Twitter handles enough text every day to fill Tolstoy's War and Peace more than 8,163 times over. Twitter reckons it would take you 31 years to read all the output it generates in a single day.
So, let's just put it this way; the Cloud is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think that it's a long way down the road to the chemist's, but...
In Your Pocket
At the same time as being massive though, the Cloud's nature as a form of online storage and distributed processing allows it to be so portable that you could have a portal into it in your pocket - and you've doubtlessly used it multiple times today. Email, Facebook, Twitter; when we access these services from our phones then it's easy to think of them as running locally, but the reality is that they operate solely in the Cloud. The apps you have on your smartphone are merely a front-end for that massive, digital world.
Facebook's Prineville data centre, which opened in 2011, was the first data centre the company had designed itself.
Facebook doesn't run on your phone; like the rest of the Cloud it runs simultaneously in one of three custom-built data centres, or one of the many across the world which Facebook leases. We may think that our uploaded photos are kept safely close by, but in reality they draw security from being safely far away - in buildings full of hard drives, rather than on our phones or computers themselves.
That's just as well though; Facebook stores over 100 petabytes worth of just photos and video, which is too much to store in any other way. A petabyte is one quadrillion bytes.
Where are our photos, likes and tags really being stored? In places such as Forest City, North Carolina, where Facebook recently opened its second stateside data centre. Under construction since November 2010, the Forest City data centre has taken over 2,000 people more than 1.2 million hours to build and, according to Facebook, will be used to push forward a number of the social network's on-going Cloud initiatives.
The need for Facebook to keep its Cloud in pace with user demand is a pressing one, especially as more and more users begin to access Facebook from smartphones instead of more powerful desktop PCs with storage to spare. At the end of last year, of Facebook's 845 million monthly active users over half had made use of a Facebook mobile app at least once - and both of those figures are rising.
Facebook isn't just attempting to keep pace with demand, however; it's aggressively expanding its influence over the smartphone market and increasing its stake in the Cloud. In April 2012, for example, Facebook acquired Instagram - a simple-seeming photo-sharing app that lets users upload stylised images to a public Cloud - for a staggering $1 billion. Many have responded by questioning the wisdom of the purchase, but a quick look at Instagram's growth reveals a method to the apparent madness; the service has gathered over 30 million accounts in just two short years and saw it's recently launched Android app downloaded over a million times in just 12 hours.
Dropbox has over 50 million users, who have used it across more than 250 million devices.
Again though, these numbers are almost too big to retain their meaning, so just rest assured that Instagram is a big deal; you just won't believe how vastly, hugely, mind-bogglingly big it is...
Nor are Facebook and Instagram unique in their size or growth. Twitter, for example, is growing at an alarming rate: it may have taken over three years for Twitter to go from zero to one billion tweets, but since 2011 it now averages one billion new tweets every five days! All of these are uploaded and then replicated across one of Twitter's data centres - and more and more of them are coming from smartphones too; in 2011 Twitter saw a 182 per cent increase in the number of users accessing Twitter from mobile devices. Now, it's reported that as much as 55 per cent of all Twitter traffic comes from smartphones, be it through an official Twitter app or through a third party front end, such as Tweetdeck.
The Cloud's attachment to smartphones retains relevance outside the world of micro-blogging and social networking too. Cloud storage company Dropbox, which lets users upload any data they want to online storage, has over 50 million users - who have together accessed their files across 250 million different devices, including phones and tablets. The mobile versions of the free Dropbox software have been downloaded millions of times on Blackberry, Android and iOS and help see a billion different files synced to Dropbox storage every 48 hours.
Even the deeper finances of the company seem unusually grand; Dropbox recently revealed that U2's Bono is one of its core investors and that the company had been valued at over $4 billion. That's four Instagrams!
Head in the Clouds
While the Cloud caters for nearly all our storage needs though, the solution is more impressive than it is elegant once you scratch the surface. The data centres, which store all the information are styled in direct contrast to the sleek smartphones and tablets the data is accessed on; colossal, factory-like buildings containing server racks which require industrial cooling systems.
While data centres could hardly be called graceful however, they are the only viable means to store the sheer quantity of data being handled - YouTube users alone upload 48 hours of video every minute. That equates to eight years of video every day from just a single company, every single second of which is available to smartphones and PCs across the world.
Google, YouTube's parent company, remains secretive on how it manages to organise this data and regards most information about it's many data centres as a trade secret. Some details do slip out which help convey the scale of the storage being handled, however. In 2011, for example, Google established a new data centre in an abandoned paper mill on the Finnish coast, which generated such heat that Google used local seawater inlets to cool the servers. The solution turned out to be both more cost-effective and also more environmentally sound.
Google's recently launched G Drive links Google Documents with a Google Cloud.
Google has been one of the major proponents of the Cloud throughout it's history, having recently launched a new competitor to Dropbox called G Drive, which offers universal access to files through any Internet connected device. Google's pricing may be less initially generous than Dropbox's - Dropbox offers 2GB for free, while Google offers only 1GB - but scale is on Google's side since individual users can pay for up to 16TB of space. That's enough to store 32,000 hours of audio recorded at CD quality, or the RAM data of IBM's Watson supercomputer.
More interestingly, Google's G Drive integrates with some of its other services too, such as Google Docs. This means that, not only is it possible to access your files on everything from a friend's laptop to your smartphone, but it's possible to create files in the Cloud too. All you'd need do is whip out your 'phone, log in and specify which type of file you want to create. All of the processing, from the spell-checking to data organisation, is done in the Cloud using distributed computing.
Or, to give a more illustrative example; this sentence was written on a smartphone, while travelling from Derbyshire to London on the train. The next paragraph was written on a brand new PC, which pulled the in-progress article out of the Cloud and into Google's Chrome web browser, along with all the bookmarks and log-in information from the office computer. Not a single character was lost at any point and none of the files were stored locally on any of the three devices. Technology is marvellous.
OnLive is pioneering cloud-based gaming on mobile devices.
Even this is still only the start of Cloud's uses, however, with Cloud gaming services such as OnLive recently spreading to smartphones and tablets too. OnLive continues to refuse to give out any specific details regarding growth, but when testing the new Onlive iPad client by playing leading console titles such as LA Noire it was hard to imagine the concept might prove unpopular. OnLive and its competitors, such as Gaikai, enable users to stay perpetually plugged into their media - as do mobile clients of video-sharing services.
iOS users aren't left out of the scramble for Cloud dominance either, as Apple's iCloud system offers mobile syncing for everything from contact books to music and entire applications. iCloud not only offers a generous 5GB of free storage to users, but stands apart in how easily it syncs device-relevant data, such as to-do lists and Internet bookmarks. The service has already swelled to 125 million users, easily eclipsing competitors such as Dropbox thanks to being a proprietary service in a more closed market.
The surge in Cloud popularity over the last few years is only the beginning, however. As the Internet continues to revolutionise the way we interact with our media, smartphones and tablets push expectations of how and where we can interact; making the Cloud both a more viable future for computing and storage as a whole. Companies such as Google and Apple have already extended their services in such a way that they blur the line between desktop and 'phone and it's a process which shows no sign of slowing as more advanced networks and more widespread Wi-Fi coverage become available.
To many it has become an interesting and possibly inevitable future for mobile computing - that the devices themselves will get less advanced on a local scale, without losing any capability at all. Google has already made steps into the world of totally Cloud-driven computers with the Chromebook and, while progress may have been unsteady, there's no sign that the Cloud itself is in retreat.
In fact, already companies are considering the notion of an 'intercloud', or Cloud of Clouds, which extrapolates the Internet's network of networks models to mass-scale Cloud computing. First suggested in 2007 by Kevin Kelly, founding editor of Wired, the intercloud is a theoretical attempt to address Cloud saturation - that is, the possibility of a Cloud filling with data or being unable to meet user demand. Because data centres take so long to establish, the intercloud would function by networking many Clouds together; fill up one and the slack is picked up by the others.
At first glance, the concept of an intercloud seems ludicrous, due in part to the huge scales involved - is it really possible that a service such as Google, with its sea-cooled data centres, could succumb to Cloud saturation or be unable to keep pace with demand? Think on the issue more closely however - consider that smartphones ensure an increasingly tech-savvy, connected and inquisitive user-base is constantly connected to the Cloud. Think back to the rate of growth, which popular services, such as Facebook, are seeing.
Suddenly, the scale of data and information as it stands at the moment feels like nothing compared to what it might be - and the intercloud starts to feel less ludicrous and more like an inevitability.
Douglas Adams may have said that the Cloud is big - "you just won't believe how vastly, hugely, mind-bogglingly big it is, etc" - but the most impressive thing about it isn't how large it is now, but that this is just the beginning.
To learn more about cloud-based gaming, read our feature: Gaming in the Cloud.
To find how Dropbox became so big, read out feature: The Dropbox Effect.