Diigo - Diigo is a powerful research tool and a knowledge-sharing community

Raindrop.io - All your articles, photos, video & content from web & apps in one place.

Pinboard - Pinboard is a personal archive for things you find online and don't want to forget.

LinkAce - A selfhosted bookmark manager with advanced features.

GGather - Effortless and organized way to store and share your bookmarks with the right mix of features.

Viralwalk - Teleport to amazing webpages all over the internet and discover new content