Trademarks are basically identifiers.  They let the relevant consuming public know what businesses are responsible for putting specific goods and services into the marketplace.  This protects both the public from confusing genuine goods and services with knockoffs from competitors, and also protects trademark holders from having the public confuse their genuine goods and services with those of competitors. 

In addition to the traditional logos we all think of, there are many non-traditional trademarks that distinguish the trademark owner using color, sound, smell, motion, or 3D designs.

Applications for non-traditional marks undergo substantial further scrutiny at the trademark office, including unique impediments in clearing the hurdles of (a) distinctiveness and (b) the functionality doctrine.

These two concepts are covered in more detail on the trademark basics page.

Sound marks can be registered, provide they are sufficiently distinctive with respect to the product or service.

The trademark office will consider some sounds to be inherently unique or distinctive, while commonplace sounds will require proof of acquired distinctiveness.

3D marks can be also registered, here again provide they are sufficiently distinctive with respect to the product or service.  3D trademarks include trade dress, which can be the appearance of the packaging trade dress or the product itself (product configuration trade dress).  As with word and other marks, packaging trade dress can be registered by virtue of being inherently distinctive, or by virtue of having achieved acquired distinctiveness (secondary meaning).  However, the trademark office never considers product configuration to be inherently distinctive, even if the product shape is non-functional. The rationale is that consumers don’t usually perceive a product’s design as identifying the source of the product. They tend to see product configuration as features rendering the product more useful and/or appealing.

There is nothing inherent in any color that makes it distinctive of a particular brand, however, a given color can be registered on the primary register if it is deemed to have achieved acquired distinctiveness (secondary meaning). By analogy to how the trademark office will consider acquired distinctiveness in other instances, the trademark office will review evidence based on how long the color has been in use, how the color has been promoted in advertising, as how much consumers identify the color with the brand, and competitors’ use of color.

As with color marks, motion (i.e., animated sequence) marks are not considered to be inherently distinctive, and need to have acquired distinctiveness while serving non-functional purposes. There are relatively fewer complications in this category than for the color, smell, and taste, but even so there are relatively few motion trademarks.

Olfactory marks may act as source identifiers, but there are very few active trademarks using scents. They were originally off limits, but can be registered provided there is acquired distinctiveness, and product uses the scent only to help identify and distinguish the brand.

Taste hasn’t been technically banned as a potential trademark, but we are unaware of any tastes or flavors that have passed the test. There is a near fatal difficulty to overcome: in order to avoid failing the functionality doctrine, the flavor could only be applied to a product that isn’t meant for human consumption, which would mean there’s no reason to taste it in the first place, and therefore identify it with a source.