What are the current numbers on the cloud storage market? market size, user demographics, content distribution (docs, photos...), growth potential?

the following is a list of the most common cloud storage providers.
1- Google Drive Free storage:5 GB annual price for20 GB: $29.88 annual price for100 GB: $59.88 Max file size allowed:10 GB Desktop apps: Windows, Mac
2- Dropbox Free storage:2 GB (Get more space through referrals.) annual price for50 GB: $99 annual price for100 GB: $199 Max file size allowed:300 MB via browser, unlimited via desktop Desktop apps: Windows, Mac, Linux
3- Apple iCloud Free storage:5 GB annual price for20 GB: $40 annual price for50 GB: $100 Max file size allowed:25 MB for free users,250 MB for paid users Desktop apps: Windows, Mac
4- Microsoft SkyDrive Free storage:7 GB annual price for20 GB: $10 annual price for100 GB: $50 Max file size allowed:2 GB Desktop apps: Windows, Mac
5- Box Free storage:5 GB annual price for25 GB: $120 annual price for50 GB: $240 Max file size allowed:25 MB Desktop apps: Windows, Mac

Great Question !!! Answer : The methodology of a cloud computing is base on highly virtualized infrastructure, most companies and organizations are having virtualization on infrastructure for daily operation and of service to SMB and end-users on a major factor of distributing resources.
The Clod storage market is evolving in the developed countries which has help companies increase in productivity with less infrastructure premises deployment.
Individual has also benefit in the cloud by moving their docs/photos/video to the cloud, giving them a leverage of any-time / anywhere access at any-point in time of access e.g office365, google docs, youtube...etc So therefore the current numbers on the cloud storage market cant be measured by a figure because people are moving into to the cloud gradually due to privacy and security standards and which balls down to record keeping or data archiving but in some cases where the cloud its been use for web application access, AD, and many more...
The market size is huge in terms of revenue at the long run because most solutions will be built on cloud base.
At the present state of cloud computing its still new to some companies or organization which are not deploying virtualizing at the moment with high cost on infrastructure.
User Demographics has increase from17% to27& of content and Apple has been the leading content provider at the moment followed by android.
The Future of this will increase within the next2year by2015 it will increase from27 to50%.
Companies are making all our gadgets to be part of our normal life and all these are through cloud computing and methodology.
Growth Potential...Like i said earlier in2015 things will change while using any mobile gadgets for our daily needs, with the help of a data storage in the cloud through the mobile gadgets.
The Future the bright and it has come to stay in transformation of nature and innovations with technology.
Be prepared to tap into the future.

i can't give you clear answer by maybe this link would be helpful https://www.deloitte.com/assets/Dcom-Global/Local%20Assets/Documents/TMT/cloud_-_market_overview_and_perspective.pdf

I will try my level best to answer question by question as follows: Q1: What’s the Market Size IDC has teamed up with EMC (EMC) for their annual Digital Universe report, which focuses solely on the amount of digital information created within a year.
Last year's volume of data,0.8 Zettabytes (or800 billion gigabytes) was an increase of62 percent on the previous year.
But the report claimed that by2020, the amount of data in the world would reach35 zettabytes - if contained on DVDs, that would mean that they could be stacked halfway to Mars.
The amount of information in the world is set to rise44-fold in the next decade according to IDC, with much of that increase coming from the rise in cloud computing.
http://www.cio.com/article/592844/Global_Data_Storage_Demands_to_Rocket_in_Next_Decade Worldwide spending growth on storage services – comprising consulting, integration, management, and support services – will achieve a moderate growth rate of6.1 percent through2005 ………… A new study by IDC reveals.
IaaS --- We don’t have any option to select other storage solution.
We need to accept only those storage solutions provided by IaaS providers.
We can it’s a storage lock in.
No Capex.
Only Opex.
COLO -- We have any option to select other storage solution.
No storage lock in.
Only Capex.
No Opex.
Private Cloud - We have any option to select other storage solution.
No storage lock in.
One can consider EMC VBLOCK – which is a market leader using FAST (Full Automatic Storage Tiering) Only Capex.
No Opex.
Storage Cost on COLO / Private Cloud depends on following two things1.
Storage vendor selection2.
Manageability Note: For performance EMC has one good offer called FAST (Full Automatic Storage Tiering) Q2: Market size, user, demographics, content, distribution (docs, photos...) growth potential...? For content (such as (docs, photos, white papers, static contents), distribution on Cloud we should go for CDN (Content Delivery Network) services from Cloud providers like Akamai, Amazon Cloud Front, Azure Cloud, (docs, photos, white papers, static contents) Potential CDN service providers1.
Akamai2.
Amazon Cloud Front3.
Azure Cloud Front4.
Cloud Flare5.
Cloud Cache6.
Edge Cast Akamai's 'EdgePlatform' comprises110,000 servers in2050 locations handling between15 to30% of all internet traffic and is optimised to eliminate long routes and slow spots as well as security threats.
The Amazon CloudFront has been designed to allow customers to deliver all their websites and content via the service, including dynamic, static and streaming content.
It is delivered by their global network of edge locations, whereby data is sourced from the closest geographical location to where the requests come from, ensuring high speed and low latency.
AWS - CDN solution now available with S3 (AWS - Simple Storage Service) The Windows Azure service is able to easily provide for customers’ growing needs as their business grows.
Easily scalable and fully automated, resources and storage can be increased within minutes via a self service online control panel.
Q3: What are the current numbers on cloud storage market? Gartner Says Worldwide External Controller-Based Disk Storage Market Grew1.9 Percent in Fourth Quarter of2012 Worldwide external controller-based (ECB) disk storage vendor revenue totaled $6.0 billion in the fourth quarter of2012, a1.9 percent increase from revenue of $5.9 billion in the fourth quarter of2011, according to Gartner, Inc.
"The fourth quarter2012 results represent the13th consecutive quarter of revenue growth, said Roger Cox, research vice president at Gartner."However, the anemic year-over-year1.9 percent growth is a reflection of the dour macroeconomics in North America and in Europe, as well as a slowing economy in the Asia/Pacific region." EMC, Hitachi/Hitachi Data Systems (HDS) and NetApp beat the year-over-year market growth rate in the fourth quarter (see Table1).
EMC gained share with its fit-for-purpose VNX, VMAX and Data Domain platforms, as well as the accretive influence of the Isilon acquisition.
After a couple of spotty quarters, and with most its platform portfolio (FAS2000/FAS3000) refreshed, coupled with improving traction of its clustered Data ONTAP operating system, NetApp realized above-market results.
With best-in-class year-over-year revenue growth performance, the high-end VSP remained Hitachi/HDS's primary strength.
Please do let me know if you need more clarification on this subject line.
Best Regards