Before you copyright something, you should do a patent search to make sure that no one else has copyrighted the same property. You can proceed with a patent search at the US Copyright Office. If the patent search turns up that no one has copyrighted the material, you should proceed.
Copyright protection applies to intellectual property such as literature, art, photos, videos, film, music, TV shows and verse. Titles of works and names are not subjected to copyright laws. This is why you will see so many songs with the same title as well as films and even books. In order to copyright your intellectual property, you have to apply to the US Copyright office. You can download a form online to complete for copyright protection. You need to complete the form and send it in, with the fee as well as the material that you want copyrighted. Once you receive confirmation that they have received your material, you can feel that it is under copyright protection.
Copyright protection currently lasts for 120 years, or 80 years after your death. The copyright laws are subject to change. The last time that the copyright laws were changed was in 1983. As a result, much intellectual property from 1930 to 1964 was tossed into the public domain as people did not understand that they had to renew their copyright. This includes many films, songs, books and even TV shows.
The reason that people get copyright protection is to make sure that no one passes their work off as their own. It is important to note that an idea is not subject to copyright. Only a tangible product can be copyrighted. Names and symbols are not subject to copyright but can be protected under another area of intellectual property law, a patent.
If you want to know the intellectual property that is in the public domain, you can do a patent search for this property at the US copyright office. A patent search will turn up many different properties, you will most likely recognize some of the films and music that is in there. When you do a patent search, you will note some films and songs that you know. This is mostly due to the change in the copyright law in 1983.
A patent search will not turn up common copyright, however. Common copyright is when something is published with a byline, either online or in print, but not registered with the copyright office. It is still protected under copyright law. You cannot rely on a patent search to turn up everything. You are better off to copyright only what belongs to you and that you know you have created. If you infringe upon the copyright of someone else, they can find out about this in a patent search and can proceed with litigation against you. It is relatively easy to get a copyright on your intellectual property, you need only apply with the US Copyright Office