Using the following 12 public cloud storage options, you could theoretically get 112GB of free cloud storage. But not all services are the same. Some have their pros and cons related to how large a file can be uploaded, the pricing of additional cloud storage space, integrations with various operating systems and mobile apps, and of course security precautions the vendors take.
Here are side-by-side comparisons of free cloud storage options.
Amazon Cloud Drive
Free cloud storage: 5GB
Extra storage: 20GB, $10/year; 50GB, $25/year; 100GB, $50/year; 200GB, $100/year; 1TB, $500/year. Cloud Music player: 250 imported songs free; 250,000 imported songs, $24.99/year.
More info: Music purchased and downloaded from Amazon is automatically stored in Amazon Cloud Drive for free. Service also backs up Kindle-branded tablets. Since launching in March 2011, the service has come under criticism for its access policies, which states that Amazon is allowed to use access files stored in Amazon Cloud Drive.
Apple iCloud
Free cloud storage: 5GB
Extra storage: 10GB (15GB total with 5GB free), $20/year; 50GB, $100/year.
More info: Automatically synchs files, photos, videos and even Web browsing tabs across Apple devices. Windows iCloud Control Panel is available. Apps such as Keynote, Pages and Numbers are used for document management/synchronization. Apple boasts a minimum 128-bit AES encryption for iCloud.
Box
Free cloud storage: 5GB
Extra storage: Personal account, 25GB for $9.99/month; 50GB, $19.99/month. Business account: $15/user/month, 3 to 500 users; 1TB with password-protected sharing, access management and user administration. Enterprise edition: Custom pricing, unlimited storage, offers customer branding, group access controls.
More info: Provides SSL AES 256-bit encryption behind the firewall. For business and enterprise accounts, files are stored encrypted with automatic redundancy. File size limits: 100MB for the free accounts, 1GB for paid personal accounts; Business editions have 2GB file size limit. Box allows document editing in the cloud through third-party apps, such as Zoho.
Dropbox
Free cloud storage: 5GB
Extra storage: "Pro" accounts range from 100GB, $9.99/month or $99/year, to 500GB for $49.99/month or $499/year. "Teams" account, 1TB for $795/year for 5 users and $125 for each additional user.
More info: One of the best-known public cloud storage offerings, Dropbox uses SSL AES 256-bit encryption for its Pro and Teams editions. No limit on file size when uploading from the desktop application, which works on Windows, OS X and Linux; 300MB limit when uploading from the Dropbox website. Get 500MB of extra free storage when friends register, up to 16GB. Dropbox does not allow editing of documents directly in the service.
Google Drive
Free cloud storage: 5GB -- Google Docs and files converted to Google Docs do not count against storage limit. 1GB of free photo video storage in Picasa Web Albums, unlimited storage of photos and videos (up to 15-minute videos) in Google+.
Extra storage: 25GB, $2.49/month; 100GB, $4.99/month; 200GB, $9.99/month; 1TB, $49.99/month; 16TB, $799.99/month.
More info: Google Drive allows users to store a lot more files in its cloud for free if the files are Google Docs. In many cases, files can be converted to this format simply by copying them into a Google document. Drive does have some file limits, including 2MB for converted files, or 10MB for non-Google Doc files. Spreadsheets have a 20MB limit, or 256 columns. Google Doc files can be edited in the application, but third-party apps are needed to edit non-Google Doc files, such as Microsoft Word files.
MediaFire
Free cloud storage: 50GB
Extra storage: Pro edition features 250GB for $4.50/month, and Business edition offers 1TB for $49/month.
More info: Startup MediaFire offers a large amount of cloud storage, but it only has Windows, OS X and Linux desktop applications with no mobile apps yet. For $1.50/month, users can get 50GB of storage with no advertisements through the "personal" edition. MediaFire markets its content distribution package heavily. Pro edition allows 500GB/month of content distribution through 500 one-time links per day; enterprise edition allows 4TB/month of distribution with 5,000 links per day. The free edition has 200MB file size limit, while personal has a 1GB file size limit. Pro has a 4GB file size limit and business has a 10GB individual file size limit.
Microsoft SkyDrive
Free cloud storage: 7GB
Extra storage: 20GB, $10/year; 50GB, $25/year; 100GB, $50/year.
More info: Microsoft SkyDrive, which has a Windows 8-style interface, offers users one of the largest initial free storage accounts of the major cloud offerings. It does limit uploads to 300MB files via the Web browser and it has a 2GB limit via the desktop application, which can be run in Windows and OS X. It also supports iOS, Android and Windows phone apps. It includes a "forgot something" feature that allows users to remotely retrieve a file on their PC that has not uploaded to the cloud.
MiMedia
Free cloud storage: 7GB
Extra storage: 100GB, $4.99/month; 500GB, $20/month or $199/year; 1TB, $35/month or $325/year.
More info: MiMedia offers one of the higher amounts of free cloud storage in the market. It bills itself as being a backup repository and cloud-access tool specifically for media, although it works the same with documents. For large uploads, the company will send a hard drive onto which you can upload an initial dump of information, then send it back to the company for uploading to MiMedia's cloud. Files are encrypted during upload transmission but not while stored on MiMedia servers. MiMedia does not yet support Mac OS X. It does have iOS and Android apps.
SpiderOak
Free cloud storage: 2GB
Extra storage: $10 per month or $100 per year for each additional 100GB increment.
More info: SpiderOak presents itself as the secure public cloud storage option. Boasting a "zero-knowledge" policy, SpiderOak's program does not store passwords of customers, and all customer data is encrypted both in transmission and while in storage, using salted hashes and a combination of 2048-bit RSA and 256-bit AES encryption. For developers of the crowd, the company has also begun open sourcing some of the code used to create the product. SpiderOak offers personal, business and partner/reseller versions of its cloud service.
SugarSync
Free cloud storage: 5GB
Extra storage: 30GB, $4.99/month or $49.99/year; 60GB, $9.99/month or $99.99/year; 500GB, $39.99/month or $399.99/year. Business account offers 100GB for three users for $29.99/month or $299.99/year.
More info: Up to 32GB of free additional storage available if you recommend others that sign up for the service. SugarSync has mobile apps available on iOS, Android, BlackBerry, Symbian and WinMobile platforms.
Symform
Free cloud storage: Up to 10GB
Extra storage: Symform offers by far the largest amount of potentially free storage, but there's a catch. Its public cloud uses storage space donated by users, meaning other customers' encrypted data will be stored on your system when you contribute to the Symform cloud. The amount of storage each user gets is based on how much storage they contribute back to the Symform public cloud network. So, for example, if you contribute 2TB of storage, you can get 1TB of storage for free. Common use cases for this is around disaster recovery and backup. Customers can pay for the storage instead of contributing back excess storage space as well. Symform encrypts files using 256-bit AES, then divides files stored in the cloud into 64 blocks which are distributed throughout the Symform cloud network so that no one single user has access to a customer's complete set of encrypted data.
Syncplicity
Free cloud storage: 2GB
Extra storage: 50GB, $15/month for personal edition.
More info: Syncplicity is owned by EMC. Pricing for business edition, which includes central access controls, start at $45/month with tiered pricing for up to unlimited storage. No file size limit or number of files. AES 256-bit encryption is used in transmission and at rest.
Network World staff writer Brandon Butler covers cloud computing and social collaboration. He can be reached at BButler@nww.com and found on Twitter at @BButlerNWW.