Shared folders are ideal for groups of people interested in collaborating on a set of files or folders together. Add other members to a folder and its files will appear in your friends or colleagues own Dropbox just as it does in yours. You can share any folder in your Dropbox or create a new shared folder from the Dropbox website.
How secure is Dropbox?
Your files are actually safer while stored in your Dropbox than on your computer in some cases. We use the same secure methods as banks.
Dropbox takes the security of your files and of our software very seriously. We use the best tools and engineering practices available to build our software, and we have smart people making sure that Dropbox remains secure. Your files are backed-up, stored securely, and password-protected.
Other Dropbox users can't see your private files in Dropbox unless you deliberately invite them or put them in your Public folder. Everything in your Public folder is, by definition, accessible to anyone.