Sharaza lets you share a single file.
Bittorrent lets you share a single folder.
Webfs lets you share a filesystem. This includes being able to update files, change permissions, ban people (or domains) from viewing. and just generally allowing you to use it like you would any other drive. (albiet with some extra software required)
These details are provided for information only. No information here is legal advice and should not be used as such.