Pocket - When you find something you want to view later, put it in Pocket.
Tweetflick - Save, organize & find Tweets to get the most out of Twitter
Raindrop.io - All your articles, photos, video & content from web & apps in one place.
Bookmark OS - Bookmark OS is like Mac or Windows optimized for bookmarks.
Diigo - Diigo is a powerful research tool and a knowledge-sharing community
Bookmark It - Create awesome notes on YouTube videos