Google Docs - Create a new document and edit with others at the same time -- from your computer, phone or tablet. Get stuff done with or without an internet connection. Use Docs to edit Word files. Free from Google.
Zotero - Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research.
Airborn - Create and edit documents online without sacrificing your privacy
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.
Bit.ai - Bit is a smart real-time document collaboration platform for teams to create interactive documents, manage digital content and track document insights.
JabRef - Graphical Java application for managing bibtex (. bib) databases.JabRef · JabRef Help · JabRef | Blog · OpenOffice/LibreOffice .