Treehouse pretty much hits those points. They have a library of videos and tutorials across a variety of topics. This content is organized intro tracks, which a

Treehouse pretty much hits those points. They have a library of videos and tutorials across a variety of topics. This content is organized intro tracks, which are tailored collections from the library so you can track your progress of learning a specific discipline. Some of these tracks share the same subtasks. There is a public ranking system for users based on points. You receive points for watching videos, completing quizzes, and doing code challenges. It's pretty meaningless, but these points are categorized based on what type of track they were earned from, so you can see what people are most recently learning. They don't tailor their notifications to specific niches. You always get a Netflix like notification whenever they upload new content. Their feed doesn't have the option to sort by what's trending/popular either. It's a relatively expensive service and is criticized for being pretty dumbed-down in how they deliver learning material, but I think it can be useful.