A service mark does the same thing as a trademark, but while trademarks promote products, service marks promote services and events. Some familiar service marks are: Kinko’s (photocopying service), Blockbuster (video rental service), and the FedEx logo (delivery services).

In order to be eligible for trademark protection, a word or phrase must be “distinctive” — unique enough to help customers recognize a particular product in the marketplace — rather than generic, like “The Coffee House.”

i.e.

Nike

Microsoft

Barnes and Noble

They are all TM-ed. trade mark names. essentially so nobody like you or i can use part of their business name and all the time they took to build a profitable and reputable business, and use it to our advantage.

=)