Clues are visual, audio, or odiferous tools used by product sellers, service providers and marketing companies to help customers to either remember their products or services or that implies or suggests an important feature or aspect of a particular product or serivice or of the general catagory that the product or service belongs. Although some clues may also qualify as a trademark, they are often ‘functional’ that prohibits them for qualifying as a trademark. For example, in the early 2000’s -the Harvey Davidson company unsuccessfully tried to trademark the classic sound of the Harvey Davidson motorcycle. Today, the company still uses the sound of its motorcycle as a ‘clue’ in its advertising. Other well known examples of ‘clues’ are: Santa Claus’ red suit was actually changed by Coca Cola to match the ‘red’ color associated with Coca Cola Company’s ads (Santa Claus’ suit was green prior to 1950).
When considering trademarks also consider possible ‘clues’.