Bookmark It - Create awesome notes on YouTube videos
Todoist - Todoist is a to-do list that helps you get organized, at work and in life.
PageMarker - Save, organize, annotate and revisit your bookmarks
Todo - Todo is a to-do and task list app.
Bookmark OS - Bookmark OS is like Mac or Windows optimized for bookmarks.
Prodeus - Track your time learning on YouTube to earn your free degree