A backup and storage service on the Internet. Cloud storage providers generally let users upload any size and type of computer file, whereas e-mail attachments often have limitations. Also called "online storage" and "public cloud storage," a customer's files are downloaded to anyone's computer with a Web browser and password. Many providers are freemium based, offering limited free storage and higher capacities for monthly fees. Others charge per-gigabyte-per-month. Backup or Storage Although any remote storage can be used to upload a file for backup, providers dedicated to backup perform automatic uploading and may keep multiple revisions of a file, whereas companies that focus on storage and sharing do not. Also called "cyberlockers," such storage services make it easy to invite people to download files and notify the customer when the invitation is accepted. See media locker. Synchronization Keeping the same files in sync on every user's device is another feature of many storage providers. The major platform companies such as Microsoft, Apple and Google tout their cloud synchronization as an incentive to keep users within the fold. See e-mail attachment. Content Management/Delivery Cloud storage providers that keep data for automatic downloading to a user's application or open Web page fall under the "content management" umbrella (see CDN). See cloud computing, cloud storage gateway, cloud music storage, S3 cloud storage, Amazon Glacier, external storage and media sharing site.