Sarah Robson has a WordPress.com blog on the Free plan.
Infinidad.Marketing
Infinidad will have a WordPress.com website on the Business plan.
Lovethe.Earth
Lovethe.Earth has a WordPress.com website on the Business plan.
Mustard Seed Training
Mustard Seed Training had a WordPress.com blog on the Premium plan.
Sierra Club Water Sentinels
Water Sentinels have a Drupal page on the Sierra Club's national website.