I think it really depends on whether you want to advance the breadth or depth of your knowledge. If you want to go breadth, meaning touch a little bit of here

I think it really depends on whether you want to advance the breadth or depth of your knowledge. If you want to go breadth, meaning touch a little bit of here and there, yes you can rely on the internet. There are many non-fiction books can help you in this direction, but you do not have to read them. But if you want to go depth in a particular field, I think you have to read at least some most important books in that field. I do not believe you can learn an advanced field, say quantum physics, by just watching youtube videos or reading online articles. The reason is that many in depth knowledge are only presented in books. For programming, I think yes you can definitely become a programmer by learning online. But then again, if you want to be an expert in a particular field of programming, you have to read books in that field. Even for data mining and AI those kind of stuff, there are good online courses, but I don't believe online materials can cover important details as in books. The most cutting edge materials are usually presented in research papers or conference presentations.