Dropbox is one of best data sharing tool available right now. Lots of organizations are using it to share data across different machines and different platforms. But for this you should be ready to keep your data over the dropbox servers, which is not really acceptable in a lot of organizations and with lot of people. For that you need to have something on your servers, which you can monitor and control on your own. For that there are few open source solution are available but out of those, OwnCloud is something which I find most matured one available.