Mendeley - Easily organize your papers, read & annotate your PDFs, collaborate in private or open groups, and securely access your research from everywhere.
Community Questions for Confluence - Keep questions and answers in one place with an engaging, community-driven Q&A discussion forum, powered by Confluence
Zotero - Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research.
Question2Answer - A Q&A site helps an online community to share knowledge.
Qiqqa - Qiqqa is a free research and reference management software. It can be used in many organizational projects from the academic to the personal to the business endeavor. Read more about Qiqqa.
Stack Overflow for Teams - Everything you love about Stack Overflow in a private space.