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

Mendeley - Easily organize your papers, read & annotate your PDFs, collaborate in private or open groups, and securely access your research from everywhere.

Pinboard - Pinboard is a personal archive for things you find online and don't want to forget.

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

Pocket - When you find something you want to view later, put it in Pocket.

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.