There was a post on Reddit a few weeks ago, where someone asked "What is something you have learned completely via the internet?".
One of the replies was from a guy (Iamnotthatotherguy) who spent 2 hours each night, 4 days a week, dedicated to learning math online. He referenced the MIT Open Courseware courses, and the Kahn Academy as his primary sources. He spent 2 years on this schedule, and no claims to know most of the mathematical areas quite well. I think his goal was statistical learning and AI, and it sounds like he got there.
One of the replies was from a guy (Iamnotthatotherguy) who spent 2 hours each night, 4 days a week, dedicated to learning math online. He referenced the MIT Open Courseware courses, and the Kahn Academy as his primary sources. He spent 2 years on this schedule, and no claims to know most of the mathematical areas quite well. I think his goal was statistical learning and AI, and it sounds like he got there.