Raindrop.io - All your articles, photos, video & content from web & apps in one place.
Oozled - Curated resources for everything design related
Tagpacker - A free tool to quickly collect, organize, and share your favorite links.
WD Stack - Curated resources for frontend designers/developers
Diigo - Diigo is a powerful research tool and a knowledge-sharing community
PromoteProject - PromoteProject is a site where you can showcase your startup, blog posts, software, games and books.