You can share files with anyone, including people without Dropbox accounts, by sharing a link to any file or folder. You can send a shared link by email, Facebook, Twitter, instant message, social networks, wherever you want.
Shared links are view-only, and by default anyone with the link can view and download its contents.
Sharing using shared folders
If you need to work with someone on files, you can create a shared folder. Files in shared folders sync between members’ Dropbox accounts, so each member of a shared folder needs a Dropbox account.