Currently Being ModeratedMay 2, 2012 2:41 PM (in response to osteophil)
Are you referring to the paid Dropbox service? If you are, I suggest visiting their site for more information:
If you are referring to the Drop Box in your Public folder then you will need to enable file sharing so that your system is visible on the network and listed under the 'shared' section in the finder window. Other people can then connect to your system to gain access to the Drop Box inside the Public folder so that they can deposit files in your Drop Box.