File synchronisation services like Dropbox, Skydrive, iCloud and Ubuntu One are being increasingly used in organisations. The services themselves provide convenience and are often more secure than alternatives like email and FTP. They can directly enhance the productivity of an organisation by lowering the time required to keep documents and other files synced between users.
These services, however, are often not included in the overall security strategy of the organisation, instead being limited using firewall rules and maybe a line in the information security policy.
Even if the file transfer itself be secure (Dropbox has had vulnerabilities in the past), there are security issues specific to file synchronisation services that must be taken into account when considering how they should be used in your environment: