This is actually a trick question – the answer is, “not much”. Generally, trademarks refer to source-identifying marks used in connection with goods (products) and service marks are used for the same purpose, but in connection with services. The associated rights – to be able to preclude others from using a confusingly similar mark in connection with similar goods or services – are the same.
But one important way in which they are different is the way in which an applicant for registration of a mark with the U.S. Patent & Trademark Office (“PTO”) demonstrates that it is using the mark in commerce. Whether an applicant applies for registration of a mark based on actual use in commerce (§ 1(a)) or based upon a bona fide intent to use the mark in commerce (“ITU” – § 1(b)), each applicant must at some point during the prosecution of its application submit an example (“Specimen”) of how the mark is used in commerce in connection with the specific goods or services. (For more about the trademark application process, see Common Questions: What’s Involved in Registering a U.S. Trademark.)
Acceptable Specimens for Trademarks
Simply put, if an applicant seeks to demonstrate use of its mark in connection with goods, it must show the mark as used in the process of selling or offering to sell those goods to the purchasing public. Examples of such use include: