Firefox Sync - Bring your Firefox bookmarks, tabs, or passwords wherever you go with Firefox Sync. Share between computers and mobile devices. Get Firefox now!
Do this! - A simple to-do list for sharing with anyone
Raindrop.io - All your articles, photos, video & content from web & apps in one place.
Plexie - A Better Way for Teams to Create and Share Information.
Diigo - Diigo is a powerful research tool and a knowledge-sharing community
Thinkery - Thinkery is a lightweight tool for storing notes, bookmarks, todos, organized through hashtags and bookmarks are stored in full-text runs on Android and iOS app.