LinkLocker - LinkLocker is a lightweight bookmarking service with an emphasis on privacy.
Diigo - Diigo is a powerful research tool and a knowledge-sharing community
Bookmark2 - Bookmarks2 is a powerful productivity tool that makes is much easier for anyone to save their links...
Linkman - Linkman Pro allows for managing large amount of URLs in its own database.
Raindrop.io - All your articles, photos, video & content from web & apps in one place.
Sitebar - SiteBar is an Online Bookmark Manager.