Homepage.ninja - Homepage helps you to save and organize your links.
Raindrop.io - All your articles, photos, video & content from web & apps in one place.
Highlights by Learning Paths - Highlight, add private notes and tags across the web.
Pocket - When you find something you want to view later, put it in Pocket.
Panelio - Panelio helps you to save and organize your links.
Basket - A note taking application for KDE. Lots of features.