Raindrop.io - All your articles, photos, video & content from web & apps in one place.
Diigo - Diigo is a powerful research tool and a knowledge-sharing community
Pinboard - Pinboard is a personal archive for things you find online and don't want to forget.
Omnivore - Omnivore allows developers to integrate with the leading POS systems, and connects restaurants to the latest technologies.
Pocket - When you find something you want to view later, put it in Pocket.
Tweetbase - Turn Twitter into knowledge base