A blogger who wishes to remain anonymous sentd in this email he received from Automattic, Inc., the company that develops WordPress:
I work for Automattic Inc. We run wordpress.com and we own the WordPress trademark. We have noticed that you are using the WordPress name in your [domainname.com] domain and product without our permission. We are asking you to stop using our trademark to market your [services]. Please let us know how long it will take you to change the name of your site and product.
January 25, 2003: Mike tells Matt Mullenweg that if he’s interested in forking b2 that he’s interested in helping out and the WordPress project begins.
March 28, 2003: WordPress.org registered by Matt.
May 27, 2003: First release of WordPress.
January 3, 2004: WordPress 1.0 released.
August 2005: Matt founds Automattic, Inc. to spearhead the development of the WordPress codebase as well as WordPress.com.
March 1, 2006: Automattic, Inc. registers WordPress as a registered trademark.  
October 2006: Automattic, Inc. begins notifying owners of domain names containing the word ‘wordpress’ that they must rename their products and services immediately.
I think this is a bit clumsy: three years after the domain name is registered and 1 year after incorporation, WordPress is filed with the USPTO as a trademark. The only relevant discussion in the support forum is from September of last year and doesn’t include any input from Automattic staff.
Automattic, Inc. could add the trademark language at the bottom of the page on the WordPress.org and WordPress.com sites as well as add the Â® notice on the logos.
That language could link to their page explaining the policy linked to in the About section of the WordPress.org site but it looks like it wasn’t added until after April 2005.
Automattic, Inc. could have a friendly page explaining the use of the trademarks like Apple or Google do. I easily got permission and the proper language to use for featuring Six Apart’s TypePad product in my book, Blogwild.
They could offer a request to put “WordPress is a registered trademark of Automattic, Inc.” or some other notice so that consumers will realize that the domain owner are not representatives of Automattic, Inc. Sort of like what is on WordPressPodcast.org:
WordPress is a trademark of Automattic, Inc., used with permission. The WordPress Community is an informal user’s group dedicated to WordPress evangelism and is not officially affiliated with Automattic, Inc. or the WordPress Open Source project.
And yes. WordPress is open source and free as in speech and free as in beer. But before panties get bunched…
There are prior cases of trademarks being used to protect and license open source software. Consider Linux (Red Hat Linux, Ubuntu Linux, etc). A bit of a row ensued when some guy registered Linux before Linux creator Linux Torvalds did and eventually a lawsuit transferred ownership to Linus. In this case, the Linux software is free and open-source but the name of the software is a registered and licensed trademark to prevent abuse, dilution or confusion of the Linux name, project and software. The Linux Mark Institute is the body responsible for licensing and they include easy instructions on what to do to use the Linux domain name properly and with correct attribution.
I think this is what Automattic, Inc. should do: give us boilerplate disclaimer to use on our pages and products.
The WordPress development team and surrounding community contribute every single day into making WordPress a fantastic piece of software used by millions of people all over the world. Then there are folks like me that make a living teaching the software to businesses and companies all over the world that don’t have the patience to master a MySQL setup or shudder at the skill of doing an FTP upload. I have already sold products and services and have domain names containing the word ‘wordpress’ and now have to rebrand those products and change the names of the domains unless Automattic, Inc. decides to sub-license the WordPress trademark.
In the meantime, folks, if you are thinking of creating a WordPress product or service looks like you’re out of luck.
There are currently 169 domains registered containing the word ‘wordpress.’