Mendeley - Easily organize your papers, read & annotate your PDFs, collaborate in private or open groups, and securely access your research from everywhere.
ScreenTray - A better way to capture, annotate and share screenshots
Zotero - Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research.
Weava - Workspace to highlight, organize & collaborate on your research articles.
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.
Loops Feedback - Feedback on design ideas in minutes via 110m+ people