Do I have to include a notice with my trademark?
While using a trademark notice is not necessary to obtain or enforce rights in that trademark, there are certain advantages to providing notice. First, it lets others know that you are either claiming rights in the mark (if the TM or SM symbol is used) or that you have registered it with the Patent and Trademark Office (if the ® symbol is used). In addition, if you have not used the ® symbol in the case of a federally registered mark, in a subsequent lawsuit for trademark infringement you would not be able to seek financial damages, only an injunction preventing the other side from using the infringing mark.
Including a trademark notice with your trademark serves two additional purposes. First, it can help in the process of acquiring secondary meaning because it provides notice to the public that you are using the mark as a trademark. Second, it can help avoid genericide.