There are many myths about copyright that can get businesses into trouble. While many people understand that copyright is the legal protection of creative works like literature, music, photographs, movies and software, it can be hard to know what materials may or may not be used in today's world of exploding digi­tal content.

For example, on Jan. 16, a federal district court in New York found that a news agency infringed the copyrights in photos that a photojournalist posted on Twitter by copying the photos and distributing them to sources such as the Washington Post's website. The news agency argued that Twitter's terms of use provided it with a license to use the ­photos.

The court disagreed and held that Twitter's terms of use do not provide an unrestricted license to use posted content. While users might be able to use copyrighted material posted on Twitter within Twitter, that does not mean such material may be freely used outside of Twitter.

So what are some common copyright myths?

Myth 1: We paid for it, so we own it.

A common misconception is that paying for work done by an independent contractor means you own the work. In reality, the person who created the work owns the copyright, not the person who paid for it.

One exception to this rule is "work made for hire" such as work created by an employee for an employer, which means the non-creating party owns the copyright.

Outside the employer-employee relationship, there must be a written agreement indicating that the hiring party owns the copyright. Otherwise, the independent contractor who created the work owns the copyright.

If your company is hiring contractors to create copyrighted works (like custom software), make sure to address all copyright ownership issues in writing beforehand. Also, make sure copyright ownership is considered for all people involved in creating a work, so ask vendors whether they subcontract any of their services.

Myth 2: It's on the Internet, so it's in the public domain and may be used freely.

The Internet comprises countless copyrighted works, many of which may be copied with a simple click. But that doesn't mean the work is not protected by copyright, has been abandoned or that it is free for all to use. Even if you don't see a copyright symbol (©) online, that doesn't mean the work is not protected by copyright or otherwise free to use. Unless the work is very old (for example, created in the early 20th century), assume that it is protected.

Myth 3: If we only use a small amount, it's fair use.

Fair use is not a right; it is a defense to copyright infringement. Determining whether an allegedly infringing use of a copyrighted work is ''fair'' is one of the murkiest areas of copyright law. The only thing that can be said about fair use with certainty is that there are no clear lines. Besides, proving a use is fair is usually an expensive endeavor. Evaluating fair use requires balancing four factors: the purpose and character of the use, the nature of the copyrighted work, the amount and substantiality of the portion taken, and the effect of the use on the potential market.

Generally speaking, businesses should obtain permission to use another's copyrighted work and should learn how to obtain licenses. This will avoid the uncertainty of a fair-use defense and communicate that the company respects intellectual property rights.

Myth 4: We can copy it if we give credit.

Identifying the owner of the copyrighted material does not make its use permissible. Instead, the issue is whether the use of the copyrighted work is permitted in the first place, either as a fair use, under license or under some other exception provided by copyright law. While crediting the owner might be prudent (as the copyright owner might be less likely to object if given credit), providing credit does not transform an otherwise unauthorized use into a permitted use.

Myth 5: It's not "copyrighted" unless it's registered with the U.S. Copyright Office.

Copyright exists automatically when the work is put in a tangible medium (for example, a photo put into a digital file), whether or not the work is registered with the U.S. Copyright Office.

There are, however, benefits to registering copyrights, including that registration is a prerequisite to filing a U.S. lawsuit for copyright infringement. Also, if a work is infringed and the copyright owner registered the copyright before infringement occurred, the copyright owner could be awarded attorneys' fees and enhanced monetary damages.

Either way, it is creation, not registration, that establishes copyright.