Microsoft Sharepoint and IBM Lotus are the industry leaders in Enterprise Content Management systems. They have good support for Enterprise to have great Intranets. However, the recent Forrester report does have references to Open Source enterprise content management systems like MindTouch who are not far behind proprietary software.

Recommended Reading:

• Top Open Source Content Management Software List - WordPress, Joomla! and Drupal

• 7 Open Source Forge Platforms That Facilitate Collaborative Software Development

• Top 5 Portals for Open Innovation

• 10 Free Scrum Project Management Tool

Alfresco

Alfresco is (alternative to Microsoft SharePoint) a leading open source enterprise content management system built by the most experienced team in the industry drawn from Documentum, Vignette and Interwoven. Key features of Alfresco

• Smart Spaces
• Desktop File Access
• Auditable Content
• Workflow
• Categories
• Advanced Search
• Administration
• Web content management
• Images
• Collaboration tools

Alfresco maintains everything in a central, scalable repository making it easy to maintain. Alfresco provides Wizard based configuration. It has superior browsing and searching capabilities. All these make Alfresco a good alternative to Microsoft SharePoint.

Alfresco Community Edition is free, available for Windows and Linux, and comes without any support. Of-course, you can buy the paid edition to get the complete support from Alfresco team.

MindTouch

MindTouch is an Open Source Enterprise Collaborative Networks and powers next generation intranets, extranets and knowledge bases. With MindTouch, you can do the following;

• Corporate Intranet
• Product Documentation and Knowledge Base
• Corporate Extranet
• Web Dashboards – CRM

MindTouch was cited as a Forrester Wave Strong Performer and the best product alternative to Microsoft SharePoint and IBM Lotus.

Liferay

Liferay is a social collaboration solution for the enterprise. A complete workspace streamlines communication, saves time, builds group cohesion and raises productivity. Provides single sign-on and work the way you want to, at your convenience. Liferay Community Editions are free but without support. Enterprise editions are present with a price.

Liferay Portal ships with broad product capabilities to provide immediate return on investment:

• Content & Document Management with Microsoft Office® integration
• Web Publishing and Shared Workspaces
• Enterprise Collaboration
• Social Networking and Mashups
• Enterprise Portals and Identity Management

Liferay Social Office

• Documents: Shared document repository with Microsoft Office integration
• Communication: Team calendars, webmail, task management and contact management
• Collaboration: Integrated threaded discussions, blogs, and wikis with related content and federated search
• People: Searchable LinkedIn-style User Profiles with user tagging, user search, friends, and integrated chat

Hippo CMS and Jetspeed

Jetspeed Portal can be tightly integrated with Hippo CMS, giving you an unmatched platform for personalization and content management. Jetspeed’s track record of performance, stability and its unrivaled support for open standards, can be ideal fit for the highly scalable collaborative intranet and web architectures built on Hippo’s products.

Plone

A powerful, flexible Content Management solution that is easy to install, use and extend Plone lets non-technical people create and maintain information using only a web browser. Perfect for web sites or intranets, Plone offers superior security without sacrificing extensibility or ease of use.

Collanos – Not Open Source but Free

Collanos Workplace helps you overcome information clutter by having a single space to share, interact and collaborate with your team.

MindQuarry (Not active)

Mindquarry is/was a collaborative software platform for file sharing, task and project management, team collaboration and Wiki editing that meshes simplicity and functionality.

Magnolia

Magnolia powers the websites of enterprises in more than 100 countries on all continents of the world. It is a Content Management System favoured for its ease-of-use and availability under an Open Source license. The page editing interface enables authors to lay out content exactly as it would appear to the website visitor. Under the hood, Magnolia contains best-of-breed Java technology based on open standards to allow for tailor-made solutions. Enterprise-grade support and services are available by the vendor and partners world-wide.

Further Reading:

KnowledgeTree - is PHP-based, open source document management software that is easy to install and use across a broad range of organizations. The features included in the community edition — including workflow, version control and audit trails — help manage the document lifecycle, promote collaboration, reduce paper and ensure compliance. The extensible PHP design, as well as incorporation of open standards, such as CMIS, ensure that KnowledgeTree can be easily integrated with other systems.

Mambo - is a business-oriented open source CMS written in the PHP programming language, the world’s most popular programming language for web-based applications. The flexibility of the code and inbuilt ability to extend Mambo make it one of the most powerful content management systems available today.

WebGUI - is a content management system and web application framework, which allows for easy content management, while maintaining the ability to create and install custom applications.