The only thing U.S. law requires to copyright a website is that the website was created in a tangible form. That means that no registration is actually necessary to copyright your work because by law it's copyrighted from the moment of its creation. In the event that your work is plagiarized, however, you may need proof of copyright to stop others from unfairly using your work. The most dependable and official way of documenting online works in the U.S. is to register them with the U.S. Copyright Office's website. The government will allow you to copyright various forms of content, such as text, audio, and video.
Your website's content can most likely be deposited and registered using the electronic Copyright Office (eCO). You can find a link to the eCO on the U.S. copyright office's website. Once there, you'll need to register with a username and password. The site will then take you through the steps of listing your authorship and provide you with tools to upload and document your site's content. Choosing to copyright a website this way is cheaper than registering with mail-in papers.
If you'd rather mail in your website's content, the copyright office requires that you do so using a compact disc (CD). There is one of two ways to mail in a "hard deposit" of your work. The first and fastest way is to use Form CO, a form which can be filled in on your computer and printed out. It's important that you fill in Form CO on your computer and not by hand; the form contains a 2-D bar code which helps the copyright office quickly scan the information you've typed in. The barcode cannot read handwriting.
The other option is to print out mail-in forms that you can fill in by hand. Choosing to copyright a website this way is more expensive and time-consuming than the other methods. Chances are that, if you're looking to copyright a website, you've got the technology at hand to use one of the faster and less expensive options.
In the event of a lawsuit over the rights to your work, having your website's copyright registered with the U.S. government significantly increases the odds of winning a court battle. Some prefer to copyright a website using different and cheaper means. Attempting to document a work's copyright without registering with the government is often referred to as a poor man's copyright.
Poor man’s copyright methods vary. People used to mail themselves letters containing their work to postdate the copyright in the event that someone challenged their true ownership. Nowadays, people use the same concepts, but in more sophisticated forms. For example, there are free websites that time stamp one's website or other work to show exactly when a work was created and by whom. These methods can be effective in some legal battles, but they're far less reliable than registering something through the copyright office. Courts and judges understand what a U.S. proof of copyright is; they may not know whether a method of self-documentation is reliable.
Under the Berne Convention, a large number of countries adhere to international copyright laws to help promote protection of artistic works across all borders. Countries adhering to the Berne Convention all agree to the law that an author of a work does not have to register a copyright; the work is copyrighted from creation. If you don't live in the U.S., check whether your country follows the Berne Convention. If it doesn't, your website may not be copyrighted until you register it.