Alfresco is the commercial open source alternative for Enterprise Content Management, providing Document Management, Collaboration, Records Management, Knowledge Management, Web Content Management and Imaging.
SDL Tridion provides organizations with Web content management tools and software that simplifes online communications. With the SDL Tridion web content management solution you can quickly and easily create, manage and publish content to the Internet.
SharePoint is a business collaboration platform that enables you to connect and empower people through formal and informal business communities, within the enterprise and beyond, and to manage content throughout the information lifecycle. SharePoint’s integrated capabilities are enhanced by search technologies and by deploying customized solutions quickly and securely.