Raindrop.io - All your articles, photos, video & content from web & apps in one place.

Diigo - Diigo is a powerful research tool and a knowledge-sharing community

Tagpacker - A free tool to quickly collect, organize, and share your favorite links.

Weava - Workspace to highlight, organize & collaborate on your research articles.

Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.

Zotero - Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research.