Bookmark2 - Bookmarks2 is a powerful productivity tool that makes is much easier for anyone to save their links...
Diigo - Diigo is a powerful research tool and a knowledge-sharing community
Sitebar - SiteBar is an Online Bookmark Manager.
Linkman - Linkman Pro allows for managing large amount of URLs in its own database.
EverSync - Everhelper - Eversync
LinkLocker - LinkLocker is a lightweight bookmarking service with an emphasis on privacy.