Advanced Bookmark Search - A fast offline search engine for bookmarks that supports searching operators
LinkLocker - LinkLocker is a lightweight bookmarking service with an emphasis on privacy.
Unmark - Hosted bookmark management app
Diigo - Diigo is a powerful research tool and a knowledge-sharing community
Pocket - When you find something you want to view later, put it in Pocket.
Linkman - Linkman Pro allows for managing large amount of URLs in its own database.