Coursera

Here is a website for self-improving. Coursera
Below is their introduction from their website.


About
We believe education is a human right. Coursera's mission is to connect the world to a great education and let people learn without limits.

Mission
We are on a mission to change the world by offering classes from top universities and professors online, and for free. We envision people throughout the world, in both developed and developing countries, to learn without limits by using our platform to connect to great education that has so far been available only to a select few. We hope to empower people with education that will improve their lives, the lives of their families, and the communities they live in.

Introduction
Learn from renowned professors, watch high quality lectures online, achieve mastery via interactive assignments, and collaborate with a global community of students.