Zotero is a powerful, easy-to-use research tool that helps you gather, organize, and analyze sources and then share the results of your research. Developed by George Mason University
License: Open Source
BibSonomy is a social bookmarking tool that excels in collaborative project management and tagging, making it ideal for users focused on social sharing. In contrast, Zotero offers a robust citation management system with extensive desktop and word processor integration, making it better suited for academic research and detailed reference management.