One or more WordPress administrators decided to partner with a targeted content company to host almost 120,000 articles on high pay-per-click topics such as mortgage, asbestos, and diabetes. The articles section in question is linked off the WordPress home page and hidden from most web browsers using CSS. This content partner pays WordPress a flat fee for placement on its highly ranked site.
WordPress is a GPL-licensed product covering server and hosting costs mostly through user donations. Some WordPress developers are working on creating a WordPress foundation with non-profit status, applying for trademarks, and I am sure there are other project costs I am not aware of.
In a now closed WordPress support thread lead developer Matt Mullenweg comments on the issue raised by a member in February, noting WordPress receives a flat fee for the articles section.
Andrew Baio at Waxy jump-started the conversation around this issue.
I am personally not a fan of this method of raising funds for the development of WordPress and its foundation. I admire the success of organizations such as Wikipedia and Mozilla and their fundraising efforts. I just donated to WordPress to show my support for community-focused foundations and open-source projects.