All the cloud services apps let you perform essential cloud functions from a tablet: download files from the cloud or -- in the iPad's case -- open files from the cloud directly into compatible applications (such as Quickoffice and Documents to Go), and push files back to the cloud when necessary. Thus, you'll want to use apps that all work with the same cloud storage service; Apple's iWork suite only works with its own MobileMe service, for example. You can also access the cloud file system from Mac, Linux, and Windows desktops, or via a Web portal. Some also have apps for specific smartphone platforms, such as Android, BlackBerry, and iPhone.
Advanced capabilities vary by vendor. One trend is to support plug-in "cloud apps" to augment a provider's services by connecting it to other platforms or data sources. For example, a LinkedIn cloud app might streamline file sharing with specified LinkedIn associates. Another trend is the use of data compression and deduplication to reduce the volume of synchronized data, speeding the file-transfer process (key on relatively slow 3G networks). Compression ratios of 10:1 or better can be obtained on many data types.
The best tablet cloud services for business
Tablet cloud storage addresses one key requirement businesses crave: control over their data. Cloud storage can be backed up en masse, preserving valuable business information no matter what platform it originates from.
Beyond backup and security, the most requested features by business users -- according to cloud storage vendors' own "vote for features" pages -- are collaboration capabilities: multiple accounts, user groups, fine-grained permission controls, file locking, and version control.
No single provider delivers all of these features. In its team edition, Dropbox (one of the most widely adopted services) lets users create a group service for five or more members, with a shared storage pool and individual quotas, centralized administration, access logging, and the ability to retrieve previous versions of a file. The team package costs less than an equivalent number of individual user accounts.
Box.net's Business and Enterprise offering sports similar features and additional collaboration capabilities, including fine-grained permissions control for arbitrary user groups, audit reporting, and custom branding. The latter feature is especially helpful when sharing content with external partners, by making data ownership more visible.
Ironically, Google offers no specific Google Docs app for either tablets or phones, opting to deliver a cross-platform mobile-optimized Web portal instead. However, all Google services, including Google Docs, support open APIs that let third parties build apps to access files stored on it; Documents to Go, GoodReader, and Quickoffice all connect to Google Docs this way.
Keeping cloud-stored data secure
Business users like what they see with tablet cloud capabilities, but want specific security features, such as encryption and two-factor authentication, that aren't usually part of basic cloud products and apps.
Entry-level cloud services don't generally offer any security beyond a basic user ID and password. Data transfers and cloud storage are both unencrypted. Most cloud services, at least in their business offerings, encrypt data during transmission, usually via the SSL/TLS (HTTPS) protocol. (Dropbox is an exception: It encrypts even free account data transfers via SSL.)