Through the process of registration, through the appropriate office such as the United States Patent and Trademark Office, creates more legal power for the holder of a Trademark. When the Trademark has been registered, the ™ transforms into a ®. The circled R indicates that the Government has accepted the mark, which creates rights in the Trademark holder when trying to enforce the mark.
For example, a registered Trademark can be litigated in Federal Court. Upon registering a Trademark, the holder of the Trademark can ask the United States Customs and Border Protection to block the importing of goods that would infringe upon the Trademark. Registration also provides multiple ways to recover damages.
In brief, registering a Trademark offers the ability to have the rights and authority to protect the mark. With any other Trademark, if another company infringes on your Trademark, it may be hard to enforce. One the other hand, registering a Trademark can take a significant amount of both time and money. Please note that failure to register a Trademark could result in being unable to use the mark at all. Talk to your local business law practitioner to discuss the pros and cons of registering your Trademark.