Silverstripe

SilverStripe is a free and open source programming framework and content management system (CMS) for creating and maintaining websites. The CMS provides an intuitive web-based administration panel, allowing anyone to maintain a website without knowledge of markup or programming languages. SilverStripe's flexible development framework, known as Sapphire, lets you build extensible and database-driven sites using PHP-based objects. It's easy, powerful, and fun.

• Supports user and group permissions
• Newsletter development and delivery module
• Create blog site with comments support
• Supports e-commerce
• Supports on-site photo gallery
• Flickr support
• YouTube gallery support
• Create multiple user forums
• Google Maps support
• External authentication