You can share files with anyone, even non-Dropbox users, by getting a link to any file or folder. Once you get the link, you can send it by email, Facebook, Twitter, instant message, social networks, wherever you want. You can share these links with anyone, even if they don't have a Dropbox account.
Important note on copyrighted material
You should only use shared folders, public links, and photo galleries for files that you have the legal right to share with others (for example, documents, photos, software, music, and videos that you personally created). You do not have the right to share files unless you own the copyright in them or have been given permission by the copyright owner to share them. Purchasing or legally acquiring video, music, ebooks, or software does not give you the right to share that material with third parties over the Internet.
If you have any doubts about whether you have the legal right to share certain files, you should not share them. By using the shared folder, public folder, or photo galleries features you represent that files placed in those folders do not violate Dropbox’s Terms of Service and that you own all copyrights to them or have been given permission by the copyright owner to share them. Dropbox has adopted a policy of terminating the accounts of users who repeatedly infringe copyright or whose accounts are subject to multiple infringement allegations. If you repeatedly share files that infringe others’ copyrights, your account will be terminated.
For more information on Dropbox’s copyright policy, please visit Dropbox’s DMCA page.