Cloud storage has grown in popularity over recent years, and storage is generally a third-party, off-site, Internet-accessible data store for computer files. An advantage of cloud storage is that individuals and firms can pay for only the amount of storage actually used, and can purchase additional storage without having to purchase additional hardware (such as hard drives). Further, cloud storage services may provide additional features such as data redundancy, security (e.g., file encryption), and file sharing.

One example of a cloud storage service is Dropbox, which synchronizes files among a user’s multiple devices such as computers and smartphones (while also storing those files online for access via a web browser). For example, when a user saves a word-processing document, that document is automatically uploaded to Dropbox’s servers and is then propagated to all of the user’s other devices. Further, Dropbox stores a new version of the document each time it is saved and uploaded, thereby allowing a user to quickly and easily recover previous versions of the document. Additionally, Dropbox can propagate updated documents to devices of multiple users (such as friends and coworkers), and allows those other users to also upload a modified copy of the document for propagation. Other cloud storage services, such as Apple’s iDisk, Google Docs, and Windows Live Mesh, provide similar functionalities.