de Valk’s claim is that their plugin copies large amounts of his own work:
This plugin had copied large chunks of code from my own WordPress SEO plugin. Not just a couple of lines, hundreds, probably even thousands of lines were used and all they changed was the namespace in most cases. They added some functionality, but not a whole lot.
What’s worth pointing out here, as de Valk does in his blog post, is that the complaint is not strictly the claim of copied and redistributed code. de Valk’s SEO plugin was released under the GPL, and that means others can do exactly that with the code. de Valk’s claim is that the code plugin is being redistributed without his original copyright notice.
WPMU DEV responded to de Valk on Twitter last week, saying they would recode anything that could have been copied from his plugin. Not satisfied with the response, and that their plugin page was still up, de Valk took the next step:
All this combined made me take a next step. This morning, Incsub, the parent company of WPMU DEV, received this cease & desist letter from my lawyer. If they don’t take down the page, I will press charges and seek assistance from the Free Software Foundation and possibly the WordPress foundation. I also took action to have the plugin removed from WordPress.org. I sent an email explaining the situation, and the plugin was removed instantly, for which I thank the WordPress.org team.
You can download the cease and desist letter here, or view the text of the letter pasted below.
The letter is addressed to Mr. Farmer, or James Farmer, who runs WPMU DEV. The cease and desist was sent to WPMU DEV this morning. We’ve reached out to WPMU DEV for comment, and will update when we know more.
Cease and Desist letter to WPMU DEV
VIA COURIER SERVICE
National Registered Agents Inc.
150 South Perry ST
Montgomery, AL 36104
To the attention of Mr. Farmer
PO Box 163
Amsterdam, the Netherlands, May 26, 2011
Re: notice to cease and desist copyright infringement
Dear Mr. Farmer,
Please be advised that our firm has been retained by Yoast V.V., a private limited liability company formed under Dutch law, to represent its legal interests in the following matter.
It has come to our attention that Incsub LLC through WPMU DEV is offering for sale a WordPress plugin named WPMU DEV SEO, which provides customers a one-stop solution for optimizing their WordPress site to achieve the highest search engine rankings possible.
As you are aware, the GNU General Public License governs the copying, distribution (together: propagation) and modification of the WordPress software and all derivative works including plugins. Pursuant to the terms and conditions of this license agreement a copyright holder of a covered work grants a non-exclusive, worldwide, royalty-free license to propagate and modify the source code of his software.
This license is not without limits: the license to propagate modified copyrighted software is void and terminated automatically if the license does not add the appropriate legal and copyright notices to the source doe in a conspicuous manner.
Such is the case here. The WPMU DEV SEO plugin contains source code, which is part verbatim copy, part modified version of the source code used in the WordPress SEO plugin by YOAST. The copyright holder of the source code for this plugin is Yoast B.V.
In light of the above, we demand that Incsub immediately ceases and desists the distribution of the WPMU DEV SEO plugin until Incsub has taken the necessary steps to credit the infringing source code in the manner required by the GNU General Public License agreement.
Incsub license to propagate and modify the copyrighted source code will be reinstated if Incsub confirms in writing within ten days after the receipt of this letter that it has ceased the distribution of the copyrighted material and credited the infringing source code in the appropriate manner.
If Incsub refuses to comply with the demand we will pursue further all legal causes of action, including the filing of a lawsuit, to stop this copyright infringement and to recover damages from Incsub for the loss suffered by Yoast B.V. as a result of the infringing conduct.
This is written without prejudice to our rights, all of which are hereby expressly reserved.
J. Lucas, Esq.