Dropbox is an easy to use freemium cloud storage solution. It has a client sync utility for multiple platforms.

Papaly is a simple social bookmarking tool to manage links.

Sync.com makes it easy to store, share and access your files from anywhere.

Memotoo sync all your contacts from Gmail, Facebook, phone, Thunderbird, Outlook, etc in a single address book.

Soocial provides a synchronization service that syncs contacts between the users' computers, phones and web apps.

SpiderOak is a cloud-based backup and restore solution to protect against data loss.

Nomadesk is a leading provider of file sharing, storage and synchronization software.

git-annex is a distributed file synchronization system written in Haskell.

BusyFlow is a workspace that integrates cloud-based productivity and collaboration apps.

Zaclys ownCloud provider is a hosted ownCloud provider.