A trademark is a word, phrase, symbol or design, or a combination of words, phrases, symbols or designs, that identifies and distinguishes the source of the goods of one party from those of others. A service mark is the same as a trademark, except that it identifies and distinguishes the source of a service rather than a product. The difference between a product and a service is that a product is a tangible item such as a car motor, whereas a service is work rendered without a product. For example, a mechanic may perform a service (i.e. an oil change) on a product (i.e. your car motor).
The essential function of a trademark is so others may easily identify the origin of the entity providing products or services. For example, if you see a swoosh symbol or the golden arches you are immediately aware that the goods/services are associated with Nike or McDonalds.
People are able to obtain a trademark with the United States Patent and Trademark Office (USPTO) if the trademark can distinguish the product or services being performed by a company and will not confuse others what that source of the product/service is.
If you register your trademark with the USPTO you may put ® next to your mark, while if you are using an unregistered trademark you may put a ™ next to your mark. The minimum cost to register a trademark with the USPTO is $325, and then there may be additional prosecution fees if there are similar marks. So why should I pay the extra money to obtain a registered trademark?
By registering your trademark you can have that your rights will extend across the United States, instead of a local region afforded by having an unregistered trademark or registering your trademark with a state office.
Before obtaining a trademark, the mark will be reviewed at the USPTO by an examiner to determine if there is another company using a similar logo/mark as yours in a different region of the country. If your company is to expand in future there may be necessary legal actions for similar marks in other areas in the country. Therefore, it may be easier to alter your mark at the start rather than take legal actions in the future.
A primary reason for obtaining a trademark is for marketing purposes so potential customers may quickly associate products/services with brands. Many customers will make decisions on which products/services to purchase based on brands. If you have obtained a registered trademark you will be afforded extra protection with the US courts. For example, courts will shift burden of proofs to the other party and owners of a registered trademark will have additional legal remedies such as being able to sue for higher monetary compensation or possibly legal fees. Another reason to register a trademark is to help secure the rights in a domain name. If you have a registered trademark that appears within a disputed domain name, arbitrators will heavily favor the owners of the registered trademark within the domain name.