While Trademarks, Copyrights, Patents, and Trade Secrets each involve intangible property rights, each differ significantly from the other in what they protect and how long they protect it.
Trademarks and Service Marks
A trademark protects the name you select to associate with your product or service. In short a trademark protects your brand name. A trademark, sometimes referred to as a service mark is any word, name, symbol, device, phrase, slogan, logo, sound, or any combination of these items whose primary purpose is to identify a product or service and distinguish it from those of another. For simplicity sake, we will refer to these items as a "mark". When a mark refers to a product it is called a trademark. When a mark refers to a service, it is called a service mark. When a mark entails a product's packaging, shape, or appearance it is called trade dress. For a mark to be registrable at either the state or federal level, the mark must be used in commerce and either distinctive or famous. What makes a mark distinctive or famous is discussed in the Introduction to Trademarks. Trademarks last as long as the trademark is used and properly maintained.
Copyrights Are Different
As stated above, trademark law protects the mark you chose to identify your goods or services (your "brand name" or "slogan"). Copyright, on the other hand, protects a copyright owner (author of a literary work, motion picture, sound recording, computer program, ad jingle, art work, etc...) from the authorized copying of a registered work. Trademark law will not prevent others from copying your goods or services. It merely protects the mark you chose to associate with the promotion and sale of your particular goods and services. Unlike trademarks that can last indefinitely, copyright protection only lasts for the life of the author plus 70 years (unless the work is a work made for hire in which case the copyright term is different).
So What Do Patents Protect
While trademark law protects a brand name or slogan, and copyright law protects an author's original expression of his idea from unauthorized copying (but not the idea itself), patent law protects one of two things: (1) the functional features of a "novel" invention, process, machine, or product (utility patent which lasts between 17 and 20 years) and (2) an innovative ornamental designs (design patent which lasts 14 years). There are some situations where a product's trade dress can be protected both under trademark law and patent law.
Trade Secrets Explained
Trade secret laws protect unpatented inventions and know-how that have been kept secret against unauthorized use or disclosure via proper security measures and limited disclosure under properly drafted non-disclosure agreements. Two common trade secrets are: (1) customer lists and (2) the formula for a soft drink which to be protected under patent law would require disclosure and limit the protection to a maximum of 20 years.