Dustman - Firefox extension to close unused tabs.
Firefox Sync - Bring your Firefox bookmarks, tabs, or passwords wherever you go with Firefox Sync. Share between computers and mobile devices. Get Firefox now!
Tab Wrangler - Automatically closes inactive browser tabs
Raindrop.io - All your articles, photos, video & content from web & apps in one place.
Symgi - Symgi - New minimal and pure bookmark site. Open multiple or singular links from bookmark groups.
Diigo - Diigo is a powerful research tool and a knowledge-sharing community