Raindrop.io - All your articles, photos, video & content from web & apps in one place.
LinkLocker - LinkLocker is a lightweight bookmarking service with an emphasis on privacy.
Pocket - When you find something you want to view later, put it in Pocket.
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.
Linkman - Linkman Pro allows for managing large amount of URLs in its own database.