Copyright

Copyright law is different from country to country, and a copyright notice is required in about 20 countries for a work to be protected under copyright. Before 1989, all published works in the US had to contain a copyright notice, the © symbol followed by the publication date and copyright owner's name, to be protected by copyright. This is no longer the case and use of a copyright notice is now optional in the US, though they are still used.

In all countries that are members of the Berne Convention, copyright is automatic and need not be obtained through official registration with any government office. Once an idea has been reduced to tangible form, for example by securing it in a fixed medium (such as a drawing, sheet music, photograph, a videotape, or a computer file), the copyright holder is entitled to enforce his or her exclusive rights. However, while registration isn't needed to exercise copyright, in jurisdictions where the laws provide for registration, it serves as evidence of a valid copyright. The original copyright owner of the copyright may be the employer of the author rather than the author himself, if the work is a work for hire.

Source - Wikipedia