The difference is that OwnCloud is marketed as an operating system and is aimed at holding all the user's personal information. Users who aren't necessarily kno

The difference is that OwnCloud is marketed as an operating system and is aimed at holding all the user's personal information. Users who aren't necessarily knowledgeable enough to distinguish trusted and untrusted "applications". A CMS is usually used by a company and has different threat scenarios. Usually only sysadmins configure and install extensions.