@Ted Clayton -

I'm not sure that having an alternative product come to mind constitutes confusion. You can buy chocolate branded "Mozart", and Amadeus M comes to mind when you do. There is no confusion.

In certain markets, businesses have successfully trademarked such things as colours. From memory, BP owns the colour green in the gasoline business. Doesn't mean I can't adopt green as my corporate colour.

But I'm more interested in branding of goods and services that ARE related to the trademark than those that are not. In these circumstances, making up your own brand is not so appealing. I am surprised that the WordPress Foundation has been so successful in preventing those offering related products and services from using "WordPress" in their identities.

I read on an apparently authoritative site (Chilling Effects) that "fair use" of a trademark includes the following:

Nominative fair use
This is when a potential infringer (or defendant) uses the registered trademark to identify the trademark holder's product or service in conjunction with his or her own. To invoke this defense, the defendant must prove the following elements:

- the product or service cannot be readily identified without the mark
- he/she only uses as much of the mark as is necessary to identify the goods or services
- he/she does nothing with the mark to suggest that the trademark holder has given his approval to the defendant.

Clearly, if you are setting up a business selling WordPress themes, your potential customers need to know that, and an obvious way to convey it is to adopt an identity that includes the words "WordPress" and "themes". So potentially, at least, "nominative fair use" might be an effective defence (British spelling) against an allegation of infringement when using such an identity.