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

LinkAce - A selfhosted bookmark manager with advanced features.

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

GGather - Effortless and organized way to store and share your bookmarks with the right mix of features.

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