In order to use Dropbox in ROSA, you should install kfilebox package. With this package, the official Dropbox client for Linux will be installed and you will be provided with a configuration wizard.
All files synchronized with the Dropbox service will be located in the Dropbox folder in your home directory. All files that you place to that folder will be automatically uploaded to the Dropbox server.
For integration with Dolphin, please install the desktop-servicemenu package. The nautilus-dropbox package provides integration with Nautilus.
In the end of installation, you may see an error message saying "scriptlet failed, /bin/dbus-send: No such file or directory". This error doesn't affect SpiderOak client functionality and can be safely ignored.
ADrive provides a client for Linux and WebDAV access (see below), but only for Personal Premium and Business accounts. For Personal Basic accounts, the only way to work with the service is to use a web browser.
Some cloud storage services (for example, 4Shared, Egnyte, Yandex.Disk) support WebDAV access. You can setup such services in ROSA in the similar way like it is done for 2Safe (instructions, example video).